Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 

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The molecular structure of hyperthermostable aromatic aminotransferase with novel substrate specificity from Pyrococcus horikoshii.

Matsui, I.Matsui, E.Sakai, Y.Kikuchi, H.Kawarabayasi, Y.Ura, H.Kawaguchi, S.Kuramitsu, S.Harata, K.

(2000) J Biol Chem 275: 4871-4879

  • DOI: https://doi.org/10.1074/jbc.275.7.4871
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Aromatic amino acid aminotransferase (ArATPh), which has a melting temperature of 120 degrees C, is one of the most thermostable aminotransferases yet to be discovered. The crystal structure of this aminotransferase from the hyperthermophilic archaeon Pyrococcus horikoshii was determined to a resolution of 2.1 A. ArATPh has a homodimer structure in which each subunit is composed of two domains, in a manner similar to other well characterized aminotransferases. By the least square fit after superposing on a mesophilic ArAT, the ArATPh molecule exhibits a large deviation of the main chain coordinates, three shortened alpha-helices, an elongated loop connecting two domains, and a long loop transformed from an alpha-helix, which are all factors that are likely to contribute to its hyperthermostability. The pyridine ring of the cofactor pyridoxal 5'-phosphate covalently binding to Lys(233) is stacked parallel to F121 on one side and interacts with the geminal dimethyl-CH/pi groups of Val(201) on the other side. This tight stacking against the pyridine ring probably contributes to the hyperthermostability of ArATPh. Compared with other ArATs, ArATPh has a novel substrate specificity, the order of preference being Tyr > Phe > Glu > Trp > His>> Met > Leu > Asp > Asn. Its relatively weak activity against Asp is due to lack of an arginine residue corresponding to Arg(292)* (where the asterisk indicates that this is a residues supplied by the other subunit of the dimer) in pig cytosolic aspartate aminotransferase. The enzyme recognizes the aromatic substrate by hydrophobic interaction with aromatic rings (Phe(121) and Tyr(59)*) and probably recognizes acidic substrates by a hydrophilic interaction involving a hydrogen bond network with Thr(264)*.

  • Organizational Affiliation

    National Institute of Bioscience and Human Technology, Tsukuba, Ibaraki 305, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
388Pyrococcus horikoshii OT3Mutation(s): 0 
Find proteins for O59096 (Pyrococcus horikoshii (strain ATCC 700860 / DSM 12428 / JCM 9974 / NBRC 100139 / OT-3))
Explore O59096 
Go to UniProtKB:  O59096
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO59096
Sequence Annotations
  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.185 
  • R-Value Observed: 0.185 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 64.01α = 90
b = 124.87β = 90
c = 128.78γ = 90
Software Package:
Software NamePurpose
MIRPHSmodel building
MADNESSdata reduction
MERGEFdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-04-11
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description
  • Version 1.4: 2018-04-18
    Changes: Data collection