Crystal Structure of S-Adenosylmethionine Synthetase

摘要: The structure of S-adenosylmethionine synthetase (MAT, ATP:L-methionine S-adenosyltransferase, EC 2.5.1.6.) from Escherichia coli has been determined at 3.0 A resolution by multiple isomorphous replacement using a uranium derivative and the selenomethionine form enzyme (SeMAT). SeMAT data (9 residues out 383 amino acid residues) have found to sufficient phasing power determine 42,000 molecular weight protein combining them with other heavy atom (multiple replacement). consists four identical subunits; two subunits spherical tight dimer, pairs these dimers peanut-shaped tetrameric enzyme. Each pair dimer active sites which are located between subunits. subunit three domains that related each pseudo-3-fold symmetry. essential divalent (Mg2+/Co2+) monovalent (K+) metal ions one product, Pi ions, were in site separate structures.