3KKX

Neutron structure of human carbonic anhydrase II

3KKX の概要

• エントリーDOI: 10.2210/pdb3kkx/pdb
• 分子名称: Carbonic anhydrase 2, ZINC ION (3 entities in total)
• 機能のキーワード: proton transfer, neutron, hca ii, cytoplasm, lyase, metal-binding, zinc
• 由来する生物種: Homo sapiens (human)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 29354.47

構造登録者

Fisher, S.Z.,Langan, P.A. (登録日: 2009-11-06, 公開日: 2010-01-12, 最終更新日: 2023-09-06)

主引用文献

Fisher, S.Z.,Kovalevsky, A.Y.,Domsic, J.F.,Mustyakimov, M.,McKenna, R.,Silverman, D.N.,Langan, P.A.
Neutron structure of human carbonic anhydrase II: implications for proton transfer.
Biochemistry, 49:415-421, 2010

PubMed Abstract: Human carbonic anhydrase II (HCA II) catalyzes the reversible hydration of carbon dioxide to form bicarbonate and a proton. Despite many high-resolution X-ray crystal structures, mutagenesis, and kinetic data, the structural details of the active site, especially the proton transfer pathway, are unclear. A large HCA II crystal was prepared at pH 9.0 and subjected to vapor H-D exchange to replace labile hydrogens with deuteriums. Neutron diffraction studies were conducted at the Protein Crystallography Station at Los Alamos National Laboratory. The structure to 2.0 A resolution reveals several interesting active site features: (1) the Zn-bound solvent appearing to be predominantly a D(2)O molecule, (2) the orientation and hydrogen bonding pattern of solvent molecules in the active site cavity, (3) the side chain of His64 being unprotonated (neutral) and predominantly in an inward conformation pointing toward the zinc, and (4) the phenolic side chain of Tyr7 appearing to be unprotonated. The implications of these details are discussed, and a proposed mechanism for proton transfer is presented.

PubMed: 20025241
DOI: 10.1021/bi901995n

実験手法

NEUTRON DIFFRACTION (2 Å)