1OLU

Roles of His291-alpha and His146-beta' in the reductive acylation reaction catalyzed by human branched-chain alpha-ketoacid dehydrogenase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.161 

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This is version 2.0 of the entry. See complete history


Literature

Roles of His291-Alpha and His146-Beta' in the Reductive Acylation Reaction Catalyzed by Human Branched-Chain Alpha-Ketoacid Dehydrogenase: Refined Phosphorylation Loop Structure in the Active Site.

Wynn, R.M.Machius, M.Chuang, J.L.Li, J.Tomchick, D.R.Chuang, D.T.

(2003) J Biol Chem 278: 43402

  • DOI: 10.1074/jbc.M306204200
  • Primary Citation of Related Structures:  
    1OLS, 1OLU, 1OLX

  • PubMed Abstract: 
  • We report here that alterations of either His291-alpha or His146-beta' in the active site of human branched-chain alpha-ketoacid dehydrogenase (E1b) impede both the decarboxylation and the reductive acylation reactions catalyzed by E1b as well as the binding of cofactor thiamin diphosphate (ThDP) ...

    We report here that alterations of either His291-alpha or His146-beta' in the active site of human branched-chain alpha-ketoacid dehydrogenase (E1b) impede both the decarboxylation and the reductive acylation reactions catalyzed by E1b as well as the binding of cofactor thiamin diphosphate (ThDP). In a refined human E1b active-site structure, His291-alpha, which aligns with His407 in Escherichia coli pyruvate dehydrogenase and His263 in yeast transketolase, is on a largely ordered phosphorylation loop. The imidazole ring of His291-alpha in E1b coordinates to the terminal phosphate oxygen atoms of bound ThDP. The N3 atom of wild-type His146-beta', which can be protonated, binds a water molecule and points toward the aminopyrimidine ring of ThDP. Remarkably, the H291A-alpha mutation results in a complete order-to-disorder transition of the loop region, which precludes the binding of the substrate lipoyl-bearing domain to E1b. The H146A-beta' mutation, on the other hand, does not alter the loop structure, but nullifies the reductive acylation activity of E1b. Our results suggest that: 1) His291-alpha plays a structural rather than a catalytic role in the binding of cofactor ThDP and the lipoyl-bearing domain to E1b, and 2) His146-beta' is an essential catalytic residue, probably functioning as a proton donor in the reductive acylation of lipoamide on the lipoyl-bearing domain.


    Related Citations: 
    • Roles of Active Site and Novel K+ Ion-Binding Site Residues in Human Mitochondrial Branched-Chain Alpha-Ketoacid Decarboxylase/Dehydrogenase
      Wynn, R.M., Ho, R., Chuang, J.L., Chuang, D.T.
      (2003) J Biol Chem 274: 4168
    • Crystal Structure of Human Branched-Chain Alpha-Ketoacid Dehydrogenase and the Molecular Basis of Multienzyme Complex Deficiency in Maple Syrup Urine Disease
      Aevarsson, A., Chuang, J.L., Wynn, R.M., Turley, S., Chuang, D.T., Hol, W.G.J.
      (2000) Structure 8: 277

    Organizational Affiliation

    Departments of Biochemistry and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9038, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
2-OXOISOVALERATE DEHYDROGENASE ALPHA SUBUNITA400Homo sapiensMutation(s): 1 
Gene Names: BCKDHA
EC: 1.2.4.4
UniProt & NIH Common Fund Data Resources
Find proteins for P12694 (Homo sapiens)
Explore P12694 
Go to UniProtKB:  P12694
PHAROS:  P12694
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP12694
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
2-OXOISOVALERATE DEHYDROGENASE BETA SUBUNITB342Homo sapiensMutation(s): 0 
Gene Names: BCKDHB
EC: 1.2.4.4
UniProt & NIH Common Fund Data Resources
Find proteins for P21953 (Homo sapiens)
Explore P21953 
Go to UniProtKB:  P21953
PHAROS:  P21953
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP21953
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.161 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 145.379α = 90
b = 145.379β = 90
c = 69.497γ = 120
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-08-28
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2019-05-15
    Changes: Data collection, Experimental preparation, Other
  • Version 1.4: 2019-09-25
    Changes: Data collection, Experimental preparation, Other
  • Version 2.0: 2021-08-04
    Changes: Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary