Enzyme Research

Volume 2012 (2012), Article ID 845465, 8 pages

doi:10.1155/2012/845465

Research Article

In Silico Characterization of Histidine Acid Phytase Sequences

Vinod Kumar,1,2 Gopal Singh,¹ A. K. Verma,¹ and Sanjeev Agrawal¹

¹Department of Biochemistry, G. B. Pant University of Agriculture & Technology, Pantnagar 263145, India

²Akal School of Biotechnology, Eternal University, Baru Sahib, Sirmour 173101, India

Received 27 August 2012; Accepted 19 November 2012

Academic Editor: Jose M. Guisan

Copyright © 2012 Vinod Kumar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Histidine acid phytases (HAPhy) are widely distributed enzymes among bacteria, fungi, plants, and some animal tissues. They have a significant role as an animal feed enzyme and in the solubilization of insoluble phosphates and minerals present in the form of phytic acid complex. A set of 50 reference protein sequences representing HAPhy were retrieved from NCBI protein database and characterized for various biochemical properties, multiple sequence alignment (MSA), homology search, phylogenetic analysis, motifs, and superfamily search. MSA using MEGA5 revealed the presence of conserved sequences at N-terminal “RHGXRXP” and C-terminal “HD.” Phylogenetic tree analysis indicates the presence of three clusters representing different HAPhy, that is, PhyA, PhyB, and AppA. Analysis of 10 commonly distributed motifs in the sequences indicates the presence of signature sequence for each class. Motif 1 “SPFCDLFTHEEWIQYDYLQSLGKYYGYGAGNPLGPAQGIGF” was present in 38 protein sequences representing clusters 1 (PhyA) and 2 (PhyB). Cluster 3 (AppA) contains motif 9 “KKGCPQSGQVAIIADVDERTRKTGEAFAAGLAPDCAITVHTQADTSSPDP” as a signature sequence. All sequences belong to histidine acid phosphatase family as resulted from superfamily search. No conserved sequence representing 3- or 6-phytase could be identified using multiple sequence alignment. This in silico analysis might contribute in the classification and future genetic engineering of this most diverse class of phytase.

1. Introduction

Phytate (myo-inositol 1,2,3,4,5,6-hexakisphosphate; IP₆) is the major storage form of phosphorus (P), representing approximately 80% of P in soil [1], 65–80% of total P in grains [2], and up to 80% of P in manures from monogastric animals [3]. Phytate exists primarily as metal phytate complex with nutritionally important cations, that is, Ca²⁺, Fe²⁺, and Zn²⁺ [4].

Phytases (IP₆ phosphohydrolase) are a class of phosphatases which catalyses hydrolysis of phytate to inositol phosphates, inorganic phosphorus, and myo-inositol [5], also lowers down affinity of phytate to associated minerals and proteins [6], and thus increases bioavailability of P, minerals, and proteins for growth and development of plants and animals [7–9].

Phytases are widely distributed among plants [10, 11], certain animal tissues, and microbial cells [12–15]. To date, four classes of phytases have been characterized in terrestrial organisms: histidine acid phytase (HAPhy), cysteine phytase (CPhy), purple acid phosphatase (PAP), and -propeller phytase (BPPhy) [16, 17]. HAPhys are the most studied and diverse class of phytase. Most bacterial, fungal, and plant phytases belong to histidine acid phosphatases (EC 3.1.3.2) which are further classified as 3-phytase (EC 3.1.3.8) or 6-phytase (EC 3.1.3.26) due to their high specific activity for phytate and position specific initial hydrolysis of phytate.

Phytases have been extensively reviewed for various industrial and biotechnological applications [18–21], biochemical properties [22], and consensus phytase construct [23]. Conserved amino acid residues are reported in HAPhy sequences at N-terminal “RHGXRXP,” C-terminal “HD,” and eight cysteine residues in around sequence [16, 24, 25]. It is a well-adopted fact that all phytases have not similar and common active site; hence the initial classification system is based on catalytic mechanism [22]. Still, there is a need to devise a taxonomic system to accommodate new types of phytases with novel catalytic mechanism.

The in silico characterization of protein sequences of industrially important enzymes has been reported recently [26–28]. Biochemical features, homology search, multiple sequence alignment, phylogenetic tree construction, motif, and superfamily distribution of alkaline proteases have been analyzed using various bioinformatics tools [28]. A total of 121 protein sequences of pectate lyases were subjected to homology search, multiple sequence alignment, phylogenetic tree construction, and motif analysis [26]. Malviya et al. [27] collected forty-seven full-length amino acid sequences of PPO from bacteria, fungi, and plants and subjected them to multiple sequence alignment (MSA), domain identification, and phylogenetic tree construction.

In the present study, we performed in silico analysis of 50 HAPhy protein sequences. The biochemical features, homology search, multiple sequence alignment, phylogenetic tree construction, motif, and superfamily distribution have been analyzed using various bioinformatics tools.

2. Material and Methods

Representative genes from histidine acid phytases (E. coli AppA, GenBank accession number P07102; Aspergillus niger PhyA and PhyB, P34752 and P34754) were used as probes to BLAST microbial genome database from NCBI (http://www.ncbi.nlm.nih.gov/). The protein sequences in FASTA format from RefSeq entries, which were shown to exhibit phytase activities, were selected for further in silico study.

Physiochemical data were generated from various tools in the EXPASY proteomic server (ClustalW, ProtParam, protein calculator, Compute pI/Mw, ProtScale) [29]. The molecular weights (kDa) of the various histidine acid phytases were calculated by the addition of average isotopic masses of amino acid in the protein and deducting the average isotopic mass of one water molecule. The pI of enzyme was calculated using pK values of amino acid according to Bjellqvist et al. [30].

The evolutionary history was inferred using the Neighbor-Joining method [31]. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The evolutionary distances were computed using the Poisson correction method [32] and are in the units of the number of amino acid substitutions per site. All positions containing gaps and missing data were eliminated. There were a total of 303 positions in the final dataset. Evolutionary analyses were conducted in MEGA5 [33]. For domain search, the Pfam site (http://www.sanger.ac.uk/resources/software/) was used. Domain analysis was done using MEME (http://meme.nbcr.net/meme/) [34]. The conserved protein motifs deduced by MEME were characterized for biological function analysis using protein BLAST, and domains were studied with InterProScan providing the best possible match based on the highest similarity score.

3. Result and Discussion

The 50 protein sequences of HAPhy were retrieved from NCBI. The accession number of retrieved sequences along with species names is listed in Table 1. The sequences were characterized for homology search, multiple sequences alignment, biochemical features, phylogenetic tree construction, motifs, and superfamily search using various bioinformatics tools. Out of 50 sequences 12 sequences belong to HAPhy gene AppA, 26 sequences to PhyA, and 12 sequences to PhyB.

Table 1: List of retrieved protein sequences from NCBI/Entrez and their accession number.

S. no.
Source organism
Accession number
Total sequences

1
Escherichia coli
P07102.2, NP_415500.1, ZP_07105303.1, YP_001462212.1
4

2
Shigella boydii
YP_408643.1
1

3
Shigella flexneri
YP_688514.1
1

4
Shigella dysenteriae
ZP_07681338.1, YP_402619.1
2

5
Escherichia albertii
ZP_02904404.1
1

6
Escherichia fergusonii
YP_002384142.1
1

9
Citrobacter freundii
AAR89622.1
1

10
Aspergillus niger
P34752.1, XP_001401713.2, P34754.1, XP_001393206.1
4

11
Aspergillus oryzae
XP_001821210.1
1

12
Aspergillus awamori
P34753.1
1

13
Aspergillus flavus
XP_002376973.1
1

14
Aspergillus fumigates
XP_751964.2
1

15
Aspergillus terreus
XP_001214511.1
1

16
Neosartorya fischeri
XP_001267160.1
1

17
Aspergillus nidulans
XP_659289.1
1

18
Aspergillus clavatus
XP_001271757.1, XP_001271709.1
2

19
Penicillium chrysogenum
XP_002561094.1
1

20
Penicillium marneffei
XP_002148821.1
1

21
Ajellomyces dermatitidis
XP_002629272.1
1

22
Botryotinia fuckeliana
XP_001554147.1
1

23
Uncinocarpus reesii
XP_002542954.1
1

24
Ajellomyces capsulatus
XP_001538598.1
1

25
Sclerotinia sclerotiorum
XP_001589324.1
1

26
Coccidioides posadasii
XP_003065081.1
1

27
Trichophyton rubrum
XP_003233631.1
1

28
Arthroderma otae
XP_002849736.1
1

29
Talaromyces stipitatus
XP_002483691.1
1

30
Podospora anserina
XP_001906589.1
1

31
Trichophyton verrucosum
XP_003021635.1
1

32
Arthroderma gypseum
XP_003169494.1
1

33
Penicillium marneffei
XP_002150501.1
1

34
Arthroderma benhamiae
XP_003015622.1
1

35
Candida albicans
XP_713416.1
1

36
Candida dubliniensis
XP_002421792.1, XP_002419861.1
2

37
Candida albicans
XP_713478.1
1

38
Candida tropicalis
XP_002546108.1
1

39
Debaryomyces hansenii
XP_458051.2
1

40
Komagataella pastoris
XP_002490985.1
1

41
Saccharomyces cerevisiae
NP_009650.1
1

42
Coccidioides posadasii
XP_003072016.1
1

Multiple sequence alignment showed presence of conserved sites for HAPhy N-terminal “RHG/NXRXP” and C-terminal “HD” in all sequences as reported by other coworkers [25]. This is consistent with Pfam analysis of predicted active site residues, which in all sequences is shown to be N-terminal histidine residue present in conserved region and C-terminal aspartic acid. The histidine in N-terminal region seems as a nucleophile in the formation of a covalent phosphohistidine intermediate [35]. Aspartic acid at C-terminal “HD” sequence acts as a proton donor to the oxygen atom of the scissile phosphomonoester bond [36, 37]. No conserved sequence representing 3- or 6-phytase could be identified using multiple-sequence alignment.

The phylogenetic tree based on protein sequences revealed three major clusters. Cluster 1, a larger cluster containing 26 sequences under study, includes the majority of Aspergillus sp., Penicillium sp., Ajellomyces sp., Arthroderma sp., Trichophyton sp., Sclerotinia sp., Uncinocarpus sp., and Coccidioides sp. (Figure 1). Biochemical features for this cluster are listed in Table 2. The total number of amino acid residues ranged from 441 to 539 with variable molecular weights. pI values of this cluster ranged from 4.87 to 8.53. Variations among various phytase in this group in terms of other physiochemical parameters like positively charged and negatively charged residues, hydropathicity (GRAVY) are given in Table 2.

Table 2: Biochemical characteristics of HAPhy protein sequences.

S. no.
Accession number
Source organisms
Number of amino acids
Molecular weight
Theoretical pI
Total number of negatively charged residues (Asp + Glu)
Total number of positively charged residues (Arg + Lys)
Instability index
Aliphatic index
GRAVY
Predictive active sites by Pfam

1
P07102.2
Escherichia coli
523
56118.9
6.07
51
43
45.95
86.25
−0.221
39(H), 326(D)

2
NP_415500.1
Escherichia coli str. K-12
432
47056.8
6.26
40
37
38.08
93.08
−0.157
39(H), 326(D)

3
ZP_07105303.1
Escherichia coli MS 119-7
442
48081
6.09
41
37
39.71
92.08
−0.147
49(H), 336(D)

4
YP_001462212.1
Escherichia coli E24377A
432
47029.8
6.09
40
36
38.56
93.31
−0.138
39(H), 326(D)

5
ZP_07141224.1
Escherichia coli MS 182-1
442
48081
6.26
41
38
39.52
92.08
−0.148
49(H), 336(D)

6
YP_408643.1
Shigella boydii Sb227
432
47063.8
6.09
40
36
37.99
92.41
−0.141
39(H), 326(D)

7
YP_688514.1
Shigella flexneri
432
47105.9
5.94
40
35
38.2
92.87
−0.131
39(H), 326(D)

8
ZP_07681338.1
Shigella dysenteriae 1617
434
47354.1
5.55
42
34
38.57
93.99
−0.142
41(H), 328(D)

9
YP_402619.1
Shigella dysenteriae Sd197
434
47328
5.55
42
34
38.57
93.09
−0.152
41(H), 328(D)

10
ZP_02904404.1
Escherichia albertii
439
48000.6
9.35
33
44
37.78
96.88
−0.094
46(H), 333(D)

11
YP_002384142.1
Escherichia fergusonii
428
46608.5
8.37
32
35
40.79
93.48
−0.132
39(H), 322(D)

12
AAR89622.1
Citrobacter freundii
433
48506.5
6.29
49
47
35.09
86
−0.322
39(H), 325(D)

13
P34752.1
Aspergillus niger
467
51086
4.94
51
34
44.72
76.62
−0.211
82(H), 382(D)

14
P34753.1
Aspergillus awamori
467
51074.9
4.89
52
33
42.73
76.85
−0.221
82(H), 382(D)

15
XP_001401713.2
Aspergillus niger
497
54579.1
5.25
53
38
44.74
77.69
−0.225
112(H), 392(D)

16
XP_001821210.1
Aspergillus oryzae
466
51257.1
4.87
57
39
34.89
70.49
−0.316
81(H), 361(D)

17
XP_002376973.1
Aspergillus flavus
496
54729.2
5.11
60
46
35.72
72.7
−0.31
111(H), 391(D)

18
XP_751964.2
Aspergillus fumigates
498
54538.8
8.53
48
53
29.31
77.59
−0.197
114(H), 393(D)

19
XP_001214511.1
Aspergillus terreus
466
51088.1
5.12
51
33
35.3
72.94
−0.226
82(H), 382(D)

20
XP_001267160.1
Neosartorya fischeri
464
50787.1
6.17
47
43
31.33
73.17
−0.206
80(H), 359(D)

21
XP_659289.1
Aspergillus nidulans
463
51816.2
5.35
52
39
32.09
72.48
−0.287
80(H), 358(D)

22
XP_001271757.1
Aspergillus clavatus
465
51531.3
7.14
52
52
29.94
72.6
−0.332
81(H), 360(D)

23
XP_002561094.1
Penicillium chrysogenum
483
53668.6
7.11
51
51
46.27
69.65
−0.393
96(H), 378(D)

24
XP_002148821.1
Penicillium marneffei
465
50878
5.19
48
37
32.37
73.46
−0.172
80(H), 360(D)

25
XP_002629272.1
Ajellomyces dermatitidis
528
58565.2
6.21
55
49
44
80.49
−0.167
140(H), 420(D)

26
XP_001554147.1
Botryotinia fuckeliana
529
57902.2
5.08
55
42
40.6
69.38
−0.329
140(H), 423(D)

27
XP_002542954.1
Uncinocarpus reesii
501
56117.4
8.51
52
57
33.68
70.08
−0.448
108(H), 388(D)

28
XP_001538598.1
Ajellomyces capsulatus
441
49342.6
5.88
46
35
44.48
79.59
−0.238
53(H), 333(D)

29
XP_001589324.1
Sclerotinia sclerotiorum
465
50709.3
4.88
45
29
38.75
73.25
−0.188
76(H), 359(D)

30
XP_003065081.1
Coccidioides posadasii
539
60239.3
7.93
61
63
29.66
75.25
−0.368
145(H), 425(D)

31
XP_003233631.1
Trichophyton rubrum
474
52142.7
6.23
54
50
41.86
69.22
−0.331
87(H), 362(D)

32
XP_002849736.1
Arthroderma otae
466
51429.8
5.58
53
45
40.37
67.04
−0.33
85(H), 360(D)

33
XP_002483691.1
Talaromyces stipitatus
523
58182.2
4.9
65
42
42.55
78.7
−0.26
129(H), 409(D)

34
XP_001906589.1
Podospora anserina
514
57367.6
5.55
63
53
36.91
77.8
−0.396
125(H), 406(D)

35
XP_003021635.1
Trichophyton verrucosum
456
50332.6
6.27
53
49
41.1
66.36
−0.372
69(H), 344(D)

36
XP_003169494.1
Arthroderma gypseum
473
52338.9
6.33
54
51
38.25
67.06
−0.353
86(H), 361(D)

37
XP_002150501.1
Penicillium marneffei
510
57067.8
5.07
64
45
40.04
74.18
−0.345
116(H), 396(D)

38
XP_003015622.1
Arthroderma benhamiae
456
50490.7
6.14
54
49
43.2
65.72
−0.4
69(H), 344(D)

39
P34754.1
Aspergillus niger
479
52611.5
4.65
48
28
34.04
71.96
−0.279
82(H), 382(D)

40
XP_001393206.1
Aspergillus niger
479
52486.2
4.62
49
27
33.71
71.17
−0.289
82(H), 382(D)

41
XP_001271709.1
Aspergillus clavatus
460
50746.9
4.61
54
31
39.64
79.96
−0.17
69(H), 329(D)

42
XP_713416.1
Candida albicans
461
51283.1
5.8
48
43
29.87
74.27
−0.44
73(H), 335(D)

43
XP_002421792.1
Candida dubliniensis
462
51275.9
5.44
48
41
28.02
72.62
−0.411
73(H), 335(D)

44
XP_713478.1
Candida albicans
462
51305
5.57
48
42
27.7
71.99
−0.426
73(H), 335(D)

45
XP_002546108.1
Candida tropicalis
465
52540.6
4.41
67
35
33.65
67.74
−0.543
73(H), 337(D)

46
XP_458051.2
Debaryomyces hansenii
464
51835.7
5.13
52
37
39.65
73.1
−0.404
73(H), 337(D)

47
XP_002419861.1
Candida dubliniensis
457
52259.6
5.2
57
46
36.41
70.55
−0.493
73(H), 332(D)

48
XP_002490985.1
Komagataella pastoris
468
52690.7
4.41
68
33
37.25
84.19
−0.27
84(H), 346(D)

49
NP_009650.1
Saccharomyces cerevisiae
467
52776.5
4.43
67
36
30.82
71.46
−0.373
75(H), 338(D)

50
XP_003072016.1
Coccidioides posadasii
403
45575.2
5.82
51
42
31.24
70.97
−0.473
4(H), 269(D)

Figure 1: Phylogenetic tree constructed by NJ method based on HAPhy protein sequences.

Aliphatic index analysis reveals uniformity in this group of phytases within the range of except for some sequences of Arthroderma sp. (XP_002849736.1, XP_003169494.1, XP_003015622.1) and Trichophyton sp. (XP_003021635.1). Aliphatic index of protein measures the relative volume occupied by aliphatic side chains of the amino acids: alanine, valine, leucine, and isoleucine. Globular proteins with high aliphatic index have high thermostability, and an increase in aliphatic index increases protein thermostability [38, 39].

Cluster 2 includes 12 protein sequences and represents PhyB gene sequences including the majority of Candida sp., S. cerevisiae, C. posadasii, and D. hansenii. Total number of sequences in this group is in the range of 457 to 479, and the pI values range from 4.41 to 5.82. It has less variation in its pI as compared to cluster 1 sequences (PhyA). Aliphatic index of this cluster sequences is uniform in the range of except for Candida tropicalis (XP_002546108.1) with a value of 67.74 and Komagataella pastoris (XP_002490985.1) with a value of 84.19.

Cluster 3 represents protein sequences from phytase gene AppA, also abbreviated as PhyC [22], which includes E. coli (in majority) along with various Shigella sp. and Citrobacter freundii. Various biophysical parameters for this group of sequences reveal amino acid residues ranging from 428 to 523, while pI value of the majority of sequences is in range of 5.5 to 6.5 except for E. albertii (9.35) and E. fergusonii (8.37). Aliphatic index of this group of sequences reveals highest thermostability among all three clusters. Predominantly positively charged amino acids are present in all three clusters.

The instability index is used to measure in vivo half-life of a protein [40]. The proteins which have been reported as in vivo half-life of less than 5 hours showed instability index greater than 40, whereas those having more than 16 hours half-life [41] have an instability index of less than 40. Instability index of HAP sequences under the study is found higher than 40 (Table 2) for 15 sequences including fully characterized E. coli and A. niger phytases, indicating an in vivo half-life of less than 5 hours. Superfam tool on ExPASy server for superfamily analysis of phytase sequences reveals the identity of all sequences to histidine acid phosphatase family belonging to phosphoglycerate mutase-like superfamily [42] (Table 3).

Table 3: Distribution of superfamily among HAPhy protein sequences determined using superfam server.

Family
Superfamily
Accession number (range of amino acids residues)

Histidine acid phosphatase
Phosphoglycerate mutase-like
XP_001401713.2 (61–496), P07102.2 (26–429), NP_415500.1 (26–429), ZP_07105303.1 (36–439), YP_001462212.1 (26–429), ZP_07141224.1 (36–439), YP_408643.1 (26–429), YP_688514.1 (26–429), ZP_07681338.1 (28–431), YP_402619.1 (28–431), ZP_02904404.1 (33–436) YP_002384142.1 (27–424), AAR89622.1 (27–427), P34752.1 (30–466), P34753.1 (31–466), XP_001821210.1 (29–465), XP_002376973.1 (59–495), XP_751964.2 (62–497), XP_001214511.1 (32–466), XP_001267160.1 (28–463), XP_659289.1 (28–461), XP_001271757.1 (30–464), XP_002561094.1 (45–482), XP_002148821.1 (28–464), XP_002629272.1 (89–527), XP_001554147.1 (90–527), XP_002542954.1 (57–495), XP_001538598.1 (6–440), XP_001589324.1 (26–463), XP_003065081.1 (97–532), XP_003233631.1 (36–469), XP_002849736.1 (35–466), XP_002483691.1 (87–517), XP_001906589.1 (76–512), XP_003021635.1 (23–451), XP_003169494.1 (35–468), XP_002150501.1 (73–505), XP_003015622.1 (23–451), P34754.1 (35–470), XP_001393206.1 (35–470), XP_001271709.1 (23–452), XP_713416.1 (28–455), XP_002421792.1 (28–455), XP_713478.1 (28–455), XP_002546108.1 (28–457), XP_458051.2 (28–451), XP_002419861.1 (28–445), XP_002490985.1 (42–464), NP_009650.1 (34–460), XP_003072016.1 (1–393)

Histidine acid phytase from all three clusters shares a large / and a small -domain [22]. MEME analysis results in frequently observed 10 motifs (Table 4). A set of 41 amino acid residues “SPFCDLFTHEEWIQYDYLQSLGKYYGYGAGNPLGPAQGIGF” representing motif 1 were conserved and uniformly observed in 38 phytase protein sequences from clusters 1 and 2, that is, PhyA and PhyB, revealing their identity with HP_HAP like, histidine acid phosphatase superfamily. Other motifs are associated with HAP superfamily (Table 2). Cluster 3, representing AppA, does not have motif 1 in its sequences, but it does contain a 50 amino acid residues long unique motif 9 “KKGCPQSGQVAI IADVDERTRKTGEAFAAGLAPDCAITVHTQADTSSPDP.” Motif 5 “YAFLKTYNYSL GADDLTPFGEQQLVDSGIKFYQRYESLAKDIVPFIRASG” is present in all protein sequences representing PhyA cluster 1. PhyB protein sequences also contain a unique 41 amino acid residues long motif 8 “ETSPENSEGPYAGTTNALRHGAAFRARY GSLYDENSTLPVF.”

Table 4: Distribution of commonly observed motifs in different HAPhy protein sequences along with their functional domains.

Motifs number
Motif present in number of sequence
Motif width
Sequence
Domain

1
38
41
SPFCDLFTHEEWIQYDYLQSLGKYYGYGAGNPLGPAQGIGF
HP_HAP_like, histidine phosphatases superfamily

2
49
29
VPPGCKITFVQVLSRHGARYPTKSKSKMY
Histidine phosphatase superfamily

3
47
30
VRVLVNDRVVPLHGCLVDPLGRCKLDDFVA
Local conserved domain

4
49
29
TLYADFSHDNDMTSIFTALGLYNGTEPLS
Histidine phosphatase superfamily

5
26
50
YAFLKTYNYSLGADDLTPFGEQQLVDSGIKFYQRYESLAKDIVPFIRASG
Histidine phosphatase superfamily

6
49
29
RLNKALPGVNLTSADVVSLMDMCSFETVA
Histidine phosphatase superfamily

7
48
21
GYSAAWTVPFGARAYFEKMQC
Histidine phosphatase superfamily

8
11
50
TEIFLLQQAQGMPEPGWGRITDSHQWNTLLSLHNAQFYLLQRTPEVARSR
Local conserved domain

9
12
50
KKGCPQSGQVAIIADVDERTRKTGEAFAAGLAPDCAITVHTQADTSSPDP
Histidine phosphatase superfamily

10
9
50
TPHPPQKQAYGVTLPTSVLFIAGHDTNLANLGGALELNWTLPGQPDNTPP
Histidine phosphatase superfamily

4. Conclusion

Phylogenetic clustering and variation among biochemical features of different phytases might contribute in further classification of highly diverse HAPhys and their selection for various application purposes. Conserved sequences in motifs may be utilized for designing specific degenerate primers for identification and isolation of type and class of phytase (HAPhy) as numerous phytases are being isolated to fulfill the need of efficient phytase for feed application in various systems. Variation in biochemical features may be a key source of information for the screening of novel phytases and comparison with other classes of phytases. Functional attributes are needed to verify experimentally for conserved motifs found. This in silico analysis might be used for future genetic engineering of industrially important phytase.

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