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Publication Abstract from PubMed

We have determined the X-ray crystal structures of the NADH-dependent alcohol dehydrogenase LlAdhA from Lactococcus lactis and its laboratory-evolved variant LlAdhA(RE1) at 1.9A and 2.5A resolution, respectively. LlAdhA(RE1), which contains three amino acid mutations (Y50F, I212T, and L264V), was engineered to increase the microbial production of isobutanol (2-methylpropan-1-ol) from isobutyraldehyde (2-methylpropanal). Structural comparison of LlAdhA and LlAdhA(RE1) indicates that the enhanced activity on isobutyraldehyde stems from increases in the protein's active site size, hydrophobicity, and substrate access. Further structure-guided mutagenesis generated a quadruple mutant (Y50F/N110S/I212T/L264V), whose K(M) for isobutyraldehyde is approximately 17-fold lower and catalytic efficiency (k(cat)/K(M)) is approximately 160-fold higher than wild-type LlAdhA. Combining detailed structural information and directed evolution, we have achieved significant improvements in non-native alcohol dehydrogenase activity that will facilitate the production of next-generation fuels such as isobutanol from renewable resources.

Structure-guided engineering of Lactococcus lactis alcohol dehydrogenase LlAdhA for improved conversion of isobutyraldehyde to isobutanol.,Liu X, Bastian S, Snow CD, Brustad EM, Saleski TE, Xu JH, Meinhold P, Arnold FH J Biotechnol. 2012 Sep 3. pii: S0168-1656(12)00610-4. doi:, 10.1016/j.jbiotec.2012.08.008. PMID:22974724^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.