Patent ID: 6277615
Filing Date: 2001-08-21
Classification: A23K,C12N,C12Y

Abstract:
Modified barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme, whereby said substitution:a) maintains enzyme specificity by conserving the active site groove of said native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme; andb) effects increased thermostability over the native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EIIi) replacing glycine by proline or alanine in helices of said barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme, in order to stiffen the enzyme amino acid chain and reduce entropy of the unfolded enzyme;ii) attaching negatively charged residues to N-termini of helices in said native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme;iii) introducing ion pairs into said native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme, to increase binding energy in the folded enzyme;iv) replacing lysine by arginine in said barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme, and thereby preventing lysine glycation and increasing hydrogen bonding with other parts of the enzyme;v) replacing, by glycine, as amino acid in said native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme in which the main chain torsion angle about the N and C.sup..alpha. atoms is greater than 0.degree.; orvi) creating cysteine pairs in said native barley (1.fwdarw.3,1.fwdarw.4)-.beta.-glucanase EII enzyme which can form disulphite bonds across the C and N terminals.