1BVR

M.TB. ENOYL-ACP REDUCTASE (INHA) IN COMPLEX WITH NAD+ AND C16-FATTY-ACYL-SUBSTRATE

Summary for 1BVR

• Entry DOI: 10.2210/pdb1bvr/pdb
• Descriptor: PROTEIN (ENOYL-ACYL CARRIER PROTEIN (ACP) REDUCTASE), NICOTINAMIDE-ADENINE-DINUCLEOTIDE, TRANS-2-HEXADECENOYL-(N-ACETYL-CYSTEAMINE)-THIOESTER, ... (4 entities in total)
• Functional Keywords: nadh-dependent enoyl-acp reductase, structural genomics, psi, protein structure initiative, tb structural genomics consortium, tbsgc, oxidoreductase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 6
• Total formula weight: 175952.44

Authors

Rozwarski, D.A.,Vilcheze, C.,Sugantino, M.,Bittman, R.,Jacobs, W.,TB Structural Genomics Consortium (TBSGC) (deposition date: 1998-09-17, release date: 1999-09-17, Last modification date: 2023-08-09)

Primary citation

Rozwarski, D.A.,Vilcheze, C.,Sugantino, M.,Bittman, R.,Sacchettini, J.C.
Crystal structure of the Mycobacterium tuberculosis enoyl-ACP reductase, InhA, in complex with NAD+ and a C16 fatty acyl substrate.
J.Biol.Chem., 274:15582-15589, 1999

PubMed Abstract: Enoyl-ACP reductases participate in fatty acid biosynthesis by utilizing NADH to reduce the trans double bond between positions C2 and C3 of a fatty acyl chain linked to the acyl carrier protein. The enoyl-ACP reductase from Mycobacterium tuberculosis, known as InhA, is a member of an unusual FAS-II system that prefers longer chain fatty acyl substrates for the purpose of synthesizing mycolic acids, a major component of mycobacterial cell walls. The crystal structure of InhA in complex with NAD+ and a C16 fatty acyl substrate, trans-2-hexadecenoyl-(N-acetylcysteamine)-thioester, reveals that the substrate binds in a general "U-shaped" conformation, with the trans double bond positioned directly adjacent to the nicotinamide ring of NAD+. The side chain of Tyr158 directly interacts with the thioester carbonyl oxygen of the C16 fatty acyl substrate and therefore could help stabilize the enolate intermediate, proposed to form during substrate catalysis. Hydrophobic residues, primarily from the substrate binding loop (residues 196-219), engulf the fatty acyl chain portion of the substrate. The substrate binding loop of InhA is longer than that of other enoyl-ACP reductases and creates a deeper substrate binding crevice, consistent with the ability of InhA to recognize longer chain fatty acyl substrates.

PubMed: 10336454
DOI: 10.1074/jbc.274.22.15582

Experimental method

X-RAY DIFFRACTION (2.8 Å)