Studies on Modifying Tryptophan Residues of Man1602 and Researching Characteristics of Site-Directed mutant Man1602
英文关键词: mannanase,tryptophan,chemical modification,site-directed mutation
In order to reveal the relationship between the tryptophan residue and the activity of Man1602，the expression of Man1602 was increased，the authors studied the reaction of tryptophan-specific chemical modifier with mannanase Man1602，at the same time，according to the sequence alignment results of Man1602，the relationship between tryptophan residues and enzyme activity was deduced，the fixed position of tryptophan was fixed，and the activity of the mutant was detected. The results showed that tryptophan is the active essential amino acid of Man1602，in which the mutation of W196 and W199 sites leads to almost complete loss of enzyme activity. It can be inferred that W196 and W199 are the active centers of amino acids. W198 also has a high conservation，but its mutation did not cause the complete inactivation of the enzyme so it was concluded that W198 was an important residue to sustain the hydrophobic constant of the enzyme active site.
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