Assignment of Function to Histidines 260 and 298 by Engineering the E1 Component of the Escherichia coli 2-Oxoglutarate Dehydrogenase Complex; Substitutions That Lead to Acceptance of Substrate

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• 作者：Da Jeong Shim ; Natalia S. Nemeria ; Anand Balakrishnan ; Hetalben Patel ; Jaeyoung Song ; Junjie Wang ; Frank Jordan ; Edgardo T. Farinas
• 刊名：Biochemistry
• 出版年：2011
• 出版时间：September 6, 2011
• 年：2011
• 卷：50
• 期：35
• 页码：7705-7709
• 全文大小：220K
• 年卷期：v.50,no.35(September 6, 2011)
• ISSN：1520-4995

文摘

The first component (E1o) of the Escherichia coli 2-oxoglutarate dehydrogenase complex (OGDHc) was engineered to accept substrates lacking the 5-carboxylate group by subjecting H260 and H298 to saturation mutagenesis. Apparently, H260 is required for substrate recognition, but H298 could be replaced with hydrophobic residues of similar molecular volume. To interrogate whether the second component would allow synthesis of acyl-coenzyme A derivatives, hybrid complexes consisting of recombinant components of OGDHc (o) and pyruvate dehydrogenase (p) enzymes were constructed, suggesting that a different component is the 鈥済atekeeper鈥?for specificity for these two multienzyme complexes in bacteria, E1p for pyruvate but E2o for 2-oxoglutarate.