5X62

Crystal structure of a carnosine N-methyltransferase bound by AdoHcy

Summary for 5X62

• Entry DOI: 10.2210/pdb5x62/pdb
• Descriptor: Carnosine N-methyltransferase, S-ADENOSYL-L-HOMOCYSTEINE, SODIUM ION, ... (4 entities in total)
• Functional Keywords: methyltransferase, sam, rossmann fold, transferase
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
• Total number of polymer chains: 2
• Total formula weight: 93044.41

Authors

Xie, W.,Liu, X. (deposition date: 2017-02-20, release date: 2017-07-26, Last modification date: 2024-11-06)

Primary citation

Liu, X.,Wu, J.,Sun, Y.,Xie, W.
Substrate Recognition Mechanism of the Putative Yeast Carnosine N-methyltransferase
ACS Chem. Biol., 12:2164-2171, 2017

PubMed Abstract: Anserine (β-alanyl-N(P)-methyl-l-histidine) is a natural metabolite present in skeletal muscle and the central nervous system of vertebrates and plays important physiological roles in living organisms. The production of anserine is catalyzed by carnosine N-methyltransferases, which transfer a methyl group to carnosine (β-alanyl-l-histidine). However, the structural basis of the substrate recognition for the enzymes is unknown. We present the crystal structure of the putative carnosine N-methyltransferase from yeast named YNL092W in complex with SAH, solved by the single-wavelength anomalous dispersion (SAD) method. The protein contains a typical Rossmann domain and a characteristic N-terminal helical domain. At the cofactor-binding site, SAH forms an extensive interaction network with the enzyme. The individual contribution of each residue to ligand affinity and enzyme activity was assessed by ITC and methyltransferase assays after mutagenesis of the key residues. Additionally, docking studies and activity assays were conducted in order to identify the binding site for carnosine, and a plausible complex model was proposed. Furthermore, we discovered that two disulfide bridges might be functionally important to the enzyme. By comparison to structure- and sequence-similar methyltransferases, we deduce that the enzyme most likely acts on a protein substrate. Our structural analyses shed light on the catalytic mechanism and substrate recognition by YNL092W.

PubMed: 28654751
DOI: 10.1021/acschembio.7b00328

Experimental method

X-RAY DIFFRACTION (2.204 Å)