PDBsum entry 1heb

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protein metals links
Lyase(oxo-acid) PDB id
Protein chain
255 a.a. *
Waters ×107
* Residue conservation analysis
PDB id:
Name: Lyase(oxo-acid)
Title: Structural consequences of hydrophilic amino-acid substitutions in the hydrophobic pocket of human carbonic anhydrase ii
Structure: Carbonic anhydrase ii. Chain: a. Engineered: yes
Source: Homo sapiens. Human. Organism_taxid: 9606
2.00Å     R-factor:   0.180    
Authors: S.K.Nair,D.W.Christianson
Key ref:
S.K.Nair and D.W.Christianson (1993). Structural consequences of hydrophilic amino acid substitutions in the hydrophobic pocket of human carbonic anhydrase II. Biochemistry, 32, 4506-4514. PubMed id: 8485129 DOI: 10.1021/bi00068a005
16-Jul-92     Release date:   15-Oct-92    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P00918  (CAH2_HUMAN) -  Carbonic anhydrase 2
260 a.a.
255 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 1 residue position (black cross)

 Enzyme reactions 
   Enzyme class: E.C.  - Carbonate dehydratase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: H2CO3 = CO2 + H2O
= CO(2)
+ H(2)O
      Cofactor: Zn(2+)
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular space   11 terms 
  Biological process     angiotensin-mediated signaling pathway   21 terms 
  Biochemical function     protein binding     5 terms  


    Added reference    
DOI no: 10.1021/bi00068a005 Biochemistry 32:4506-4514 (1993)
PubMed id: 8485129  
Structural consequences of hydrophilic amino acid substitutions in the hydrophobic pocket of human carbonic anhydrase II.
S.K.Nair, D.W.Christianson.
The three-dimensional structures of Leu-198-->Glu, Leu-198-->His, Leu-198-->Arg, and Leu-198-->Ala variants of human carbonic anhydrase II (CAII) have each been determined by X-ray crystallographic methods to a resolution of 2.0 A. The side chain of Leu-198 is located at the mouth of the active site hydrophobic pocket, and this pocket is required for substrate association. Hydrophobic-->hydrophilic amino acid substitutions at the mouth of the pocket decrease kcat/KM for CO2 hydration: the CO2 hydrase activities of Leu-198-->Glu, Leu-198-->His, and Leu-198-->Arg CAIIs are diminished 19-fold, 10-fold, and 17-fold, respectively, relative to the wild-type enzyme; however, the substitution of a compact aliphatic side chain for Leu-198 has a smaller effect on catalysis, in that Leu-198-->Ala CAII exhibits only a 3-fold decrease in CO2 hydrase activity [Krebs, J. F., Rana, F., Dluhy, R. A., & Fierke, C. A. (1993) Biochemistry (preceding paper in this issue)]. It is intriguing that CO2 hydrase activity is not severely diminished in Leu-198-->Arg CAII, even though the side chain of Arg-198 blocks the hydrophobic pocket. Therefore, the bulky side chain of Arg-198 must be reasonably mobile in order to accommodate substrate association. Significantly, a residue larger than the wild-type Leu-198 side chain does not necessarily block the substrate association pocket; e.g., the side chain of Glu-198 packs against a hydrophobic patch, the net result of which is a wider mouth for the pocket.(ABSTRACT TRUNCATED AT 250 WORDS)

Literature references that cite this PDB file's key reference

  PubMed id Reference
19520834 B.Sjöblom, M.Polentarutti, and K.Djinovic-Carugo (2009).
Structural study of X-ray induced activation of carbonic anhydrase.
  Proc Natl Acad Sci U S A, 106, 10609-10613.
PDB codes: 2vva 2vvb
18335973 V.M.Krishnamurthy, G.K.Kaufman, A.R.Urbach, I.Gitlin, K.L.Gudiksen, D.B.Weibel, and G.M.Whitesides (2008).
Carbonic anhydrase as a model for biophysical and physical-organic studies of proteins and protein-ligand binding.
  Chem Rev, 108, 946.  
12056894 S.Huang, B.Sjöblom, A.E.Sauer-Eriksson, and B.H.Jonsson (2002).
Organization of an efficient carbonic anhydrase: implications for the mechanism based on structure-function studies of a T199P/C206S mutant.
  Biochemistry, 41, 7628-7635.
PDB codes: 1lg5 1lg6 1lgd
10872443 D.W.Christianson, and J.D.Cox (1999).
Catalysis by metal-activated hydroxide in zinc and manganese metalloenzymes.
  Annu Rev Biochem, 68, 33-57.  
  7757009 T.P.Lo, M.E.Murphy, J.G.Guillemette, M.Smith, and G.D.Brayer (1995).
Replacements in a conserved leucine cluster in the hydrophobic heme pocket of cytochrome c.
  Protein Sci, 4, 198-208.
PDB codes: 1csu 1csv 1csw 1csx
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