1cvb
From Proteopedia
Line 1: | Line 1: | ||
[[Image:1cvb.jpg|left|200px]] | [[Image:1cvb.jpg|left|200px]] | ||
- | + | <!-- | |
- | + | The line below this paragraph, containing "STRUCTURE_1cvb", creates the "Structure Box" on the page. | |
- | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
- | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
- | + | or leave the SCENE parameter empty for the default display. | |
- | | | + | --> |
- | | | + | {{STRUCTURE_1cvb| PDB=1cvb | SCENE= }} |
- | + | ||
- | + | ||
- | }} | + | |
'''STRUCTURAL AND FUNCTIONAL IMPORTANCE OF A CONSERVED HYDROGEN BOND NETWORK IN HUMAN CARBONIC ANHYDRASE II''' | '''STRUCTURAL AND FUNCTIONAL IMPORTANCE OF A CONSERVED HYDROGEN BOND NETWORK IN HUMAN CARBONIC ANHYDRASE II''' | ||
Line 28: | Line 25: | ||
[[Category: Christianson, D W.]] | [[Category: Christianson, D W.]] | ||
[[Category: Ippolito, J A.]] | [[Category: Ippolito, J A.]] | ||
- | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:09:01 2008'' | |
- | + | ||
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + |
Revision as of 10:09, 2 May 2008
STRUCTURAL AND FUNCTIONAL IMPORTANCE OF A CONSERVED HYDROGEN BOND NETWORK IN HUMAN CARBONIC ANHYDRASE II
Overview
Amino acid substitutions at Thr199 of human carbonic anhydrase II (CAII) (Thr199-->Ser, Ala, Val, and Pro) were characterized to investigate the importance of a conserved hydrogen bonding network. The three-dimensional structures of azide-bound and sulfate-bound T199V CAIIs were determined by x-ray crystallographic methods at 2.25 and 2.4 A, respectively (final crystallographic R factors are 0.173 and 0.174, respectively). The CO2 hydrase activities of T199S and T199P variants suggest that the side chain methyl and backbone amino functionalities stabilize the transition state by approximately 0.4 and 0.8 kcal/mol, respectively. The side chain hydroxyl group causes: stabilization of zinc-hydroxide relative to zinc-water (pKa increases approximately 2 units); stabilization of the transition state for bicarbonate dehydration relative to the CAII.HCO3- complex (approximately 5 kcal/mol); and destabilization of the CAII.HCO3- complex (approximately 0.8 kcal/mol). An inverse correlation between log(kcatCO2/KM) and the pKa of zinc-water (r = 0.95, slope = -1) indicates that the hydrogen bonding network stabilizes the chemical transition state and zinc-hydroxide similarly. These data are consistent with the hydroxyl group of Thr199 forming a hydrogen bond with the transition state and a non-hydrogen-bonded van der Waals contact with CAII.HCO3-.
About this Structure
1CVB is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Structural and functional importance of a conserved hydrogen bond network in human carbonic anhydrase II., Krebs JF, Ippolito JA, Christianson DW, Fierke CA, J Biol Chem. 1993 Dec 25;268(36):27458-66. PMID:8262987 Page seeded by OCA on Fri May 2 13:09:01 2008