1T7N
Crystal structure of the M564G mutant of murine CrAT
Summary for 1T7N
| Entry DOI | 10.2210/pdb1t7n/pdb |
| Related | 1NDB 1NDF 1NDI 1T7O 1T7Q |
| Descriptor | Carnitine acetyltransferase (2 entities in total) |
| Functional Keywords | transferase |
| Biological source | Mus musculus (house mouse) |
| Cellular location | Endoplasmic reticulum (Potential): P47934 |
| Total number of polymer chains | 1 |
| Total formula weight | 70023.05 |
| Authors | Hsiao, Y.-S.,Jogl, G.,Tong, L. (deposition date: 2004-05-10, release date: 2004-06-22, Last modification date: 2024-02-14) |
| Primary citation | Hsiao, Y.-S.,Jogl, G.,Tong, L. Structural and biochemical studies of the substrate selectivity of carnitine acetyltransferase J.Biol.Chem., 279:31584-31589, 2004 Cited by PubMed Abstract: Carnitine acyltransferases catalyze the exchange of acyl groups between coenzyme A (CoA) and carnitine. They have important roles in many cellular processes, especially the oxidation of long-chain fatty acids, and are attractive targets for drug discovery against diabetes and obesity. These enzymes are classified based on their substrate selectivity for short-chain, medium-chain, or long-chain fatty acids. Structural information on carnitine acetyltransferase suggests that residues Met-564 and Phe-565 may be important determinants of substrate selectivity with the side chain of Met-564 located in the putative binding pocket for acyl groups. Both residues are replaced by glycine in carnitine palmitoyltransferases. To assess the functional relevance of this structural observation, we have replaced these two residues with small amino acids by mutagenesis, characterized the substrate preference of the mutants, and determined the crystal structures of two of these mutants. Kinetic studies confirm that the M564G or M564A mutation is sufficient to increase the activity of the enzyme toward medium-chain substrates with hexanoyl-CoA being the preferred substrate for the M564G mutant. The crystal structures of the M564G mutant, both alone and in complex with carnitine, reveal a deep binding pocket that can accommodate the larger acyl group. We have determined the crystal structure of the F565A mutant in a ternary complex with both the carnitine and CoA substrates at a 1.8-A resolution. The F565A mutation has minor effects on the structure or the substrate preference of the enzyme. PubMed: 15155726DOI: 10.1074/jbc.M403484200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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