1DPD

CRYSTALLOGRAPHIC AND ENZYMATIC INVESTIGATIONS ON THE ROLE OF SER558, HIS610 AND ASN614 IN THE CATALYTIC MECHANISM OF AZOTOBACTER VINELANDII DIHYDROLIPOAMIDE ACETYLTRANSFERASE (E2P)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 

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This is version 1.3 of the entry. See complete history


Literature

Crystallographic and enzymatic investigations on the role of Ser558, His610, and Asn614 in the catalytic mechanism of Azotobacter vinelandii dihydrolipoamide acetyltransferase (E2p).

Hendle, J.Mattevi, A.Westphal, A.H.Spee, J.de Kok, A.Teplyakov, A.Hol, W.G.

(1995) Biochemistry 34: 4287-4298

  • DOI: https://doi.org/10.1021/bi00013a018
  • Primary Citation of Related Structures:  
    1DPB, 1DPC, 1DPD

  • PubMed Abstract: 

    Dihydrolipoamide acetyltransferase (E2p) is the structural and catalytic core of the pyruvate dehydrogenase multienzyme complex. In Azotobacter vinelandii E2p, residues Ser558, His610', and Asn614' are potentially involved in transition state stabilization, proton transfer, and activation of proton transfer, respectively. Three active site mutants, S558A, H610C, and N614D, of the catalytic domain of A. vinelandii E2p were prepared by site-directed mutagenesis and enzymatically characterized. The crystal structures of the three mutants have been determined at 2.7, 2.5, and 2.6 A resolution, respectively. The S558A and H610C mutants exhibit a strongly (200-fold and 500-fold, respectively) reduced enzymatic activity whereas the substitution of Asn614' by aspartate results in a moderate (9-fold) reduced activity. The decrease in enzymatic activity of the S558A and H610C mutants is solely due to the absence of the hydroxyl and imidazole side chains, respectively, and not due to major conformational rearrangements of the protein. Furthermore the sulfhydryl group of Cys610' is reoriented, resulting in a completely buried side chain which is quite different from the solvent-exposed imidazole group of His610' in the wild-type enzyme. The presence of Asn614' in A. vinelandii E2p is exceptional since all other 18 known dihydrolipoamide acyltransferase sequences contain an aspartate in this position. We observe no difference in conformation of Asp614' in the N614D mutant structure compared with the conformation of Asn614' in the wild-type enzyme. Detailed analysis of all available structures and sequences suggests two classes of acetyltransferases: one class with a catalytically essential His-Asn pair and one with a His-Asp-Arg triad as present in chloramphenicol acetyltransferase [Leslie, A. G. W. (1990) J. Mol. Biol. 213, 167-186] and in the proposed active site models of Escherichia coli and yeast E2p.


  • Organizational Affiliation

    Department of Biological Structure, University of Washington, Seattle 98195, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DIHYDROLIPOYL-TRANSACETYLASE243Azotobacter vinelandiiMutation(s): 0 
EC: 2.3.1.12
UniProt
Find proteins for P10802 (Azotobacter vinelandii)
Explore P10802 
Go to UniProtKB:  P10802
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP10802
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 
  • Space Group: F 4 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 224.669α = 90
b = 224.669β = 90
c = 224.669γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1995-04-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2024-02-07
    Changes: Data collection, Database references, Other