Shrivastava N Macwan AS Kohler HE Kumar A 2017 LinA-type1 and LinA-type2 are two well-characterized variants of the enzyme 'hexachlorocyclohexane (HCH)-dehydrochlorinase'. They differ from each other at ten amino acid positions and exhibit differing enantioselectivity for the transformation of the (-) and (+) enantiomers of α-HCH. Amino acids responsible for this enantioselectivity, however, are not known. An in silico docking analysis identified four amino acids (K20, L96, A131, and T133) in LinA-type1 that could be involved in selective binding of the substrates. Experimental studies with constructed mutant enzymes revealed that a combined presence of three amino acid changes in LinA-type1, i.e. K20Q, L96C, and A131G, caused a reversal in its preference from the (-) to the (+) enantiomer of α-HCH. This preference was enhanced by the additional amino acid change T133 M. Presence of these four changes also caused the reversal of enantioselectivity of LinA-type1 for δ-HCH, and β-, γ-, and δ-pentachlorocyclohexens. Thus, the residues K20, L96, A131, and T133 in LinA-type1 and the residues Q20, C96, G131, and M133 in LinA-type 2 appear to be important determinants for the enantioselectivity of LinA enzymes. application/pdf https://sonar.ch/global/documents/156090 eng info:eu-repo/semantics/altIdentifier/doi/10.1007/s10532-017-9786-9 info:eu-repo/semantics/altIdentifier/pmid/28251436 info:eu-repo/semantics/openAccess Biodegradation. - 2017 Enantioselectivity HCH dehydrochlorinase LinA α-HCH enantiomers Amino Acids Biodegradation, Environmental Chromatography, Gas Hexachlorocyclohexane Lyases Mutant Proteins Mutation Stereoisomerism Structure-Activity Relationship Important amino acid residues of hexachlorocyclohexane dehydrochlorinases (LinA) for enantioselective transformation of hexachlorocyclohexane isomers. http://purl.org/coar/resource_type/c_6501