PMID- 8477723
OWN - NLM
STAT- MEDLINE
DCOM- 19930521
LR  - 20190620
IS  - 0014-2956 (Print)
IS  - 0014-2956 (Linking)
VI  - 213
IP  - 1
DP  - 1993 Apr 1
TI  - Crystallographic studies of azide binding to human carbonic anhydrase II.
PG  - 507-15
AB  - The crystal structures of human carbonic anhydrase II (CAII) at pH 5.7 and 8.0 
      have been determined at 0.21-nm resolution in the presence of 20 mM azide, which 
      is a noncompetitive inhibitor of the CAII-catalyzed CO2 hydration reaction. 
      Although azide often facilitates the crystallization of CAII and its variants, 
      this small anion does not cause any significant structural changes in the enzyme 
      active site or in the overall protein structure, and zinc coordination remains 
      tetrahedral over the pH range 5.7-8.0. Importantly, the binding of azide at pH 
      8.0 has implications for the zinc-binding mode of the catalytic product, 
      bicarbonate ion. Since azide is a competitive inhibitor of the reverse reaction 
      of bicarbonate dehydration, and since the zinc-bound azide nitrogen makes a 
      non-hydrogen-bonded van der Waals contact with the hydroxyl group of Thr199, it 
      is possible that a zinc-bound bicarbonate oxyanion could likewise make a 
      non-hydrogen-bonded, van der Waals contact with the hydroxyl group of Thr199. 
      Therefore, the donation of a hydrogen bond to Thr199 is not absolutely required 
      for anion binding to tetracoordinate zinc.
FAU - Nair, S K
AU  - Nair SK
AD  - Department of Chemistry, University of Pennsylvania, Philadelphia 19104-6323.
FAU - Christianson, D W
AU  - Christianson DW
LA  - eng
GR  - GM07229/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Eur J Biochem
JT  - European journal of biochemistry
JID - 0107600
RN  - 0 (Azides)
RN  - EC 4.2.1.1 (Carbonic Anhydrases)
SB  - IM
MH  - Azides/*metabolism
MH  - Carbonic Anhydrases/chemistry/*metabolism
MH  - Humans
MH  - Hydrogen-Ion Concentration
MH  - Substrate Specificity
MH  - X-Ray Diffraction
EDAT- 1993/04/01 00:00
MHDA- 1993/04/01 00:01
CRDT- 1993/04/01 00:00
PHST- 1993/04/01 00:00 [pubmed]
PHST- 1993/04/01 00:01 [medline]
PHST- 1993/04/01 00:00 [entrez]
AID - 10.1111/j.1432-1033.1993.tb17788.x [doi]
PST - ppublish
SO  - Eur J Biochem. 1993 Apr 1;213(1):507-15. doi: 10.1111/j.1432-1033.1993.tb17788.x.