Protein psychrophilicity: Role of residual structural properties in adaptation of proteins to low temperatures

In order to investigate the structural distribution responsible for protein psychrophilicity, a systematic comparative analysis of 13 pairs of psychrophilic and mesophilic proteins is reported. Three kinds of residue structural states such as exposed, intermediate and buried were considered for analyzing the structural patterns of single amino acids and amino acids in different groups. The statistical test revealed that higher frequency in exposed state of Ala, higher frequency in intermediate state of His, lower frequency in buried state of Lys, lower frequency in exposed state of Gln, higher frequency in exposed state and in intermediate state of Thr, higher frequency in exposed and intermediate state of tiny and small amino acids groups could be critical factors related with protein psychrophilicity. Such structure-based differences of residual properties would help to develop a strategy for designing psychrophilic proteins.