2NN1

Structure of inhibitor binding to Carbonic Anhydrase I


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.199 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structural Analysis of Charge Discrimination in the Binding of Inhibitors to Human Carbonic Anhydrases I and II

Srivastava, D.K.Jude, K.M.Banerjee, A.L.Haldar, M.Manokaran, S.Kooren, J.Mallik, S.Christianson, D.W.

(2007) J Am Chem Soc 129: 5528-5537

  • DOI: 10.1021/ja068359w
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Despite the similarity in the active site pockets of carbonic anhydrase (CA) isozymes I and II, the binding affinities of benzenesulfonamide inhibitors are invariably higher with CA II as compared to CA I. To explore the structural basis of this mole ...

    Despite the similarity in the active site pockets of carbonic anhydrase (CA) isozymes I and II, the binding affinities of benzenesulfonamide inhibitors are invariably higher with CA II as compared to CA I. To explore the structural basis of this molecular recognition phenomenon, we have designed and synthesized simple benzenesulfonamide inhibitors substituted at the para position with positively charged, negatively charged, and neutral functional groups, and we have determined the affinities and X-ray crystal structures of their enzyme complexes. The para-substituents are designed to bind in the midsection of the 15 A deep active site cleft, where interactions with enzyme residues and solvent molecules are possible. We find that a para-substituted positively charged amino group is more poorly tolerated in the active site of CA I compared with CA II. In contrast, a para-substituted negatively charged carboxylate substituent is tolerated equally well in the active sites of both CA isozymes. Notably, enzyme-inhibitor affinity increases upon neutralization of inhibitor charged groups by amidation or esterification. These results inform the design of short molecular linkers connecting the benzenesulfonamide group and a para-substituted tail group in "two-prong" CA inhibitors: an optimal linker segment will be electronically neutral, yet capable of engaging in at least some hydrogen bond interactions with protein residues and/or solvent. Microcalorimetric data reveal that inhibitor binding to CA I is enthalpically less favorable and entropically more favorable than inhibitor binding to CA II. This contrasting behavior may arise in part from differences in active site desolvation and the conformational entropy of inhibitor binding to each isozyme active site.


    Organizational Affiliation

    Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, North Dakota 58105, USA. dk.srivastava@ndsu.nodak.edu



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Carbonic anhydrase 1A, B260Homo sapiensMutation(s): 0 
Gene Names: CA1
EC: 4.2.1.1
Find proteins for P00915 (Homo sapiens)
Explore P00915 
Go to UniProtKB:  P00915
NIH Common Fund Data Resources
PHAROS  P00915
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
M28
Query on M28

Download CCD File 
A, B
3-[4-(AMINOSULFONYL)PHENYL]PROPANOIC ACID
C9 H11 N O4 S
JUEONDBIBADVGD-UHFFFAOYSA-N
 Ligand Interaction
TRS
Query on TRS

Download CCD File 
A
2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL
C4 H12 N O3
LENZDBCJOHFCAS-UHFFFAOYSA-O
 Ligand Interaction
ZN
Query on ZN

Download CCD File 
A, B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

Download CCD File 
B
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
M28Kd:  1500   nM  Binding MOAD
M28Kd :  1500   nM  PDBBind
M28Ki:  6690   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.65 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.199 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.421α = 90
b = 71.818β = 90
c = 121.965γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
PDB_EXTRACTdata extraction
Blu-Icedata collection
HKL-2000data reduction
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-04-24
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description