... Use of Ramachandran plot for increasing thermal stability of bacterial formate dehydrogenase. ... The His263Gly mutation caused FDH destabilization and a 1.3-fold increase in the monomolecular inactivation rate constant. The replacements Ala191Gly and Asn234Gly had no significant effect on the stability. ... The stabilizing effect of the Tyr144Gly mutation was shown to be additive when introduced into the previously obtained mutant FDH with enhanced thermal stability. ...