α-crystallin is a major eye lens protein, comprising up to 40% of total lens protein. It is composed of two subunits, αA and αB and share a common central domain of about 90 residues with variable N-and C-terminal extensions. For the establishment of an evolutionary inter-relationship, an elucidation of the structure and alignment of protein sequences is crucial. In the present study, a bioinformatics approach was adopted to explore the possible structure, sequence and phylogenetic diversity of α-crystallin (both subunits αA and αB) from ten habitat-speci c sh species, (freshwater and saltwater) and compared with a standard sequence of Bos taurus species. The sequence of Bos taurus was predicted to be a close homologue of the sh species. Homology modelling has been performed in order to generate a possible '3D' structure of the crystallin proteins using SWISS-MODEL. Our analysis shows that the secondary structures of bovine α-crystallin revealed no considerable differences as compared to that of the crystallins of the habitat-speci c sh and that the presence of β-sheets was predominant in all structures. Though no signi cant differences in the αA subunits were revealed yet some structural variations were observed for αB subunits which had been con rmed by MSA analysis. The 3D structure of the protein hasn't been elucidated yet so a computational analysis estimated no major differences in structures of crystallin for either bovine or the sh species except that saltwater sh proteins possess more favourable states and higher reliabilities. In agreement with previous literature, α-crystallin has a molecular weight of 20kDa approx. and a theoretical pI of 5.75; 55.1% of its sequence is composed of hydrophilic amino acids and it is a cytosolic protein. Considerable improvement of the currently available tools is being done for a detailed understanding of the structure/function relationships of α-crystallin proteins.

α- crystallin is a major eye lens protein, comprising up to 40% of total lens protein. It is composed of two subunits, αA and αB and share a common central domain of about 90 residues with variable N- and C-terminal extensions. For the establishment of an evolutionary inter-relationship, an elucidation of the structure and alignment of protein sequences is crucial. In the present study, a bioinformatics approach was adopted to explore the possible structure, sequence and phylogenetic diversity of α-crystallin (both subunits αA and αB) from ten habitat-specific fish species, (freshwater and saltwater) and compared with a standard sequence of Bos taurus species. The sequence of Bos taurus was predicted to be a close homologue of the fish species. Homology modelling has been performed in order to generate a possible ‘3D’ structure of the crystallin proteins using SWISS-MODEL. Our analysis shows that the secondary structures of bovine α-crystallin revealed no considerable differences as compared to that of the crystallins of the habitat-specific fish and that the presence of β- sheets was predominant in all structures. Though no significant differences in the αA subunits were revealed yet some structural variations were observed for αB subunits which had been confirmed by MSA analysis. The 3D structure of the protein hasn’t been elucidated yet so a computational analysis estimated no major differences in structures of crystallin for either bovine or the fish species except that saltwater fish proteins possess more favourable states and higher reliabilities. In agreement with previous literature, α- crystallin has a molecular weight of 20kDa approx. and a theoretical pI of 5.75; 55.1% of its sequence is composed of hydrophilic amino acids and it is a cytosolic protein. Considerable improvement of the currently available tools is being done for a detailed understanding of the structure/function relationships of α- crystallin proteins.

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