1V2G

The L109P mutant of E. coli Thioesterase I/Protease I/Lysophospholipase L1 (TAP) in complexed with octanoic acid

Summary for 1V2G

• Entry DOI: 10.2210/pdb1v2g/pdb
• Related: 1IVN 1J00 1JRL 1NYV
• Descriptor: Acyl-CoA thioesterase I, SULFATE ION, IMIDAZOLE, ... (5 entities in total)
• Functional Keywords: sgnh-hydrolase fold, hydrolase
• Biological source: Escherichia coli
• Cellular location: Periplasm: P29679
• Total number of polymer chains: 1
• Total formula weight: 21854.73

Authors

Lo, Y.-C.,Lin, S.-C.,Liaw, Y.-C. (deposition date: 2003-10-15, release date: 2004-12-14, Last modification date: 2023-10-25)

Primary citation

Lo, Y.-C.,Lin, S.-C.,Shaw, J.-F.,Liaw, Y.-C.
Substrate specificities of Escherichia coli thioesterase I/protease I/lysophospholipase L1 are governed by its switch loop movement
Biochemistry, 44:1971-1979, 2005

PubMed Abstract: Escherichia coli thioesterase I/protease I/lysophospholipase L(1) (TAP) is a multifunctional lysophospholipase and acyl-CoA thioesterase with a SGNH-hydrolase fold. The relationship between TAP's structure and its versatile substrate specificity, however, is unclear. Here, we present the crystal structure of TAP in complex with octanoic acid (TAP-OCA; OCA, a free fatty acid with eight carbon atoms, C(8)). A structural comparison of native TAP with TAP-OCA reveals a remarkable conformational change in loop(75)(-)(80), called "switch loop movement", upon OCA binding to the substrate-binding crevice of TAP. OCA binding to the substrate-binding crevice results in a continuous hydrophobic surface, which triggers switch loop movement. The switch loop movement is acyl chain length dependent, with an effect of stabilizing the Michaelis complex (MC) of TAP during catalysis, and is essential for TAP's substrate preference. The finding of a sulfate ion binding site in the TAP structures, together with previous enzyme kinetic analyses, leads us to postulate that a putative CoA binding site is essential for efficient catalysis of thioesters in TAP. We also present the crystal structure of L109P-OCA (TAP's L109P mutant in complex with OCA), in which Leu109 mutated to Pro109 abolishes switch loop movement. This result strengthens our hypothesis that the switch loop movement is induced by hydrophobic interactions.

PubMed: 15697222
DOI: 10.1021/bi048109x

Experimental method

X-RAY DIFFRACTION (2 Å)