Substrate Recognition Mechanism of the Putative Yeast Carnosine N-methyltransferase

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.

Molecular Mechanism of ε-Polylysine Treatment of Animal-Derived Foods: Glycine Amidinotransferase Activity Implicates Upregulation of l-Arginine and Creatine

“…The formation of l -anserine entails the transfer of methyl groups to the histidine moiety of the carnosine catalyzed by the enzyme carnosine N -methyltransferase (CARNMT1). l -Anserine is a naturally occurring metabolite found in the central nervous system and skeletal muscle of vertebrate and plays an important physiological role in the organism . Carnosine is a histidine-derived dipeptide that exists widely in the skeletal muscle and is considered as an antioxidant .…”

“…L-Anserine is a naturally occurring metabolite found in the central nervous system and skeletal muscle of vertebrate and plays an important physiological role in the organism. 29 Carnosine is a histidinederived dipeptide that exists widely in the skeletal muscle and is considered as an antioxidant. 30 In this investigation, in goat meat supplemented with ε-polylysine, the level of carnosine (from 0.04 to 0.02 mg kg −1 ) decreased, as did the level of Lanserine (from 3.32 to 3.08 μg kg −1 ).…”

Molecular basis for histidine N1 position-specific methylation by CARNMT1

“…The SAM binding site is characteristic of a "GxGxG" (G 208 -A 209 -G 210 -L 209 -G 212 ) nucleotide-binding motif linking β1 and α2 (Supplementary information, Figure S1A); and SAM forms extensive hydrogen bonding interactions with surrounding residues that are structurally conserved between yeast and human (Supplementary information, Figure S1B). 8 The enzyme also has several additional structural elements, including four helices (αA, αB, αC and αD) from the N-terminus and an extended β hairpin (β1', β2' and αE) inserted between β2 and β3 within the core domain (Fig. 1b, c).…”

Molecular Dynamics Research of Spatial Orientation and Kinetic Energy of Active Site Collision of Carnosine under Weak Microwave Irradiation

“…24 Xie et al used the autodock program to attach carnosin ligand pairs to their binding pockets to understand the binding pattern of carnosin. 25 Several potential carnosine binding sites were discovered for experimental validation. Rossetti et al investigated carnosine degradation mechanisms by the human carnosinase enzyme.…”

“…Carnosine is a natural bioactive dipeptide with potential therapeutic effects for many diseases (e.g., diabetes and Alzheimer’s disease), relieving fatigue and aging, and as a dietary supplement to promote health. − As a nutritional supplement, carnosine can prevent and mitigate the harmful effects of COVID-19 infection . Xie et al used the autodock program to attach carnosin ligand pairs to their binding pockets to understand the binding pattern of carnosin . Several potential carnosine binding sites were discovered for experimental validation.…”