3KS3

High resolution structure of Human Carbonic Anhydrase II at 0.9 A

Summary for 3KS3

• Entry DOI: 10.2210/pdb3ks3/pdb
• Descriptor: Carbonic anhydrase 2, ZINC ION, GLYCEROL, ... (4 entities in total)
• Functional Keywords: high resolution, carbonic anhydrase, short hydrogen bond, lyase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 29446.57

Authors

Avvaru, B.S. (deposition date: 2009-11-20, release date: 2010-01-26, Last modification date: 2024-02-21)

Primary citation

Avvaru, B.S.,Kim, C.U.,Sippel, K.H.,Gruner, S.M.,Agbandje-McKenna, M.,Silverman, D.N.,McKenna, R.
A short, strong hydrogen bond in the active site of human carbonic anhydrase II.
Biochemistry, 49:249-251, 2010

PubMed Abstract: The crystal structure of human carbonic anhydrase II (HCA II) obtained at 0.9 A resolution reveals that a water molecule, termed deep water, Dw, and bound in a hydrophobic pocket of the active site forms a short, strong hydrogen bond with the zinc-bound solvent molecule, a conclusion based on the observed oxygen-oxygen distance of 2.45 A. This water structure has similarities with hydrated hydroxide found in crystals of certain inorganic complexes. The energy required to displace Dw contributes in significant part to the weak binding of CO(2) in the enzyme-substrate complex, a weak binding that enhances k(cat) for the conversion of CO(2) into bicarbonate. In addition, this short, strong hydrogen bond is expected to contribute to the low pK(a) of the zinc-bound water and to promote proton transfer in catalysis.

PubMed: 20000378
DOI: 10.1021/bi902007b

Experimental method

X-RAY DIFFRACTION (0.9 Å)