Biological Assembly 1  

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 29395.43 
• Atom Count: 2054 
• Residue Count: 260 
• Unique protein chains: 1

1LGD

Crystal Structure Analysis of HCA II Mutant T199P in Complex with Bicarbonate

• DOI: 10.2210/pdb1LGD/pdb

• Classification: LYASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): 1 


• Deposited: 2002-04-15 Released: 2002-07-24 
• Deposition Author(s): Huang, S., Sjoblom, B., Sauer-Eriksson, A.E., Jonsson, B.-H.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.9 Å
• R-Value Free: 0.214 
• R-Value Work: 0.188 

Literature

Organization of an efficient carbonic anhydrase: implications for the mechanism based on structure-function studies of a T199P/C206S mutant.

Huang, S., Sjoblom, B., Sauer-Eriksson, A.E., Jonsson, B.H.

(2002) Biochemistry 41: 7628-7635

• PubMed: 12056894 
• Primary Citation of Related Structures:  
  1LG6, 1LG5


• PubMed Abstract: 
  

Substitution of Pro for Thr199 in the active site of human carbonic anhydrase II (HCA II)(1) reduces its catalytic efficiency about 3000-fold. X-ray crystallographic structures of the T199P/C206S variant have been determined in complex with the substrate bicarbonate and with the inhibitors thiocyanate and beta-mercaptoethanol. The latter molecule is normally not an inhibitor of wild-type HCA II. All three ligands display novel binding interactions to the T199P/C206S mutant. The beta-mercaptoethanol molecule binds in the active site area with its sulfur atom tetrahedrally coordinated to the zinc ion. Thiocyanate binds tetrahedrally coordinated to the zinc ion in T199P/C206S, in contrast to its pentacoordinated binding to the zinc ion in wild-type HCA II. Bicarbonate binds to the mutant with two of its oxygens at the positions of the zinc water (Wat263) and Wat318 in wild-type HCA II. The environment of this area is more hydrophilic than the normal bicarbonate-binding site of HCA II situated in the hydrophobic part of the cavity normally occupied by the so-called deep water (Wat338). The observation of a new binding site for bicarbonate has implications for understanding the mechanism by which the main-chain amino group of Thr199 acquired an important role for orientation of the substrate during the evolution of the enzyme.

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Organizational Affiliation: 

Umeå Centre for Molecular Pathogenesis, Umeå University, SE-901 87 Umeå, Sweden.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Carbonic anhydrase II	A	260	Homo sapiens	Mutation(s): 1  Gene Names: CA2 EC: 4.2.1.1
Find proteins for P00918 (Homo sapiens) Go to Gene View: CA2 Go to UniProtKB:  P00918

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
ZN	A	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
BCT	A	BICARBONATE ION C H O3 BVKZGUZCCUSVTD-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.9 Å
• R-Value Free: 0.214 
• R-Value Work: 0.188 
• Space Group: C 1 2 1

Unit Cell:

Length (Å)	Angle (°)
a = 73.012	α = 90.00
b = 44.589	β = 92.82
c = 76.636	γ = 90.00

Software Package:

Software Name	Purpose
DENZO	data reduction
X-PLOR	model building
REFMAC	refinement
X-PLOR	phasing
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2002-04-15 
• Released Date: 2002-07-24 
• Deposition Author(s): Huang, S., Sjoblom, B., Sauer-Eriksson, A.E., Jonsson, B.-H.

Revision History 

• Version 1.0: 2002-07-24
  Type: Initial release
• Version 1.1: 2008-04-28
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance