PDBsum entry 1b5p

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Transferase PDB id
Protein chains
382 a.a. *
PO4 ×2
PLP ×2
Waters ×340
* Residue conservation analysis
PDB id:
Name: Transferase
Title: Thermus thermophilus aspartate aminotransferase double mutan
Structure: Protein (aspartate aminotransferase). Chain: a, b. Engineered: yes. Mutation: yes
Source: Thermus thermophilus. Organism_taxid: 300852. Strain: hb8. Expressed in: escherichia coli. Expression_system_taxid: 562.
Biol. unit: Dimer (from PQS)
1.80Å     R-factor:   0.193     R-free:   0.239
Authors: H.Ura,T.Nakai,S.I.Kawaguchi,I.Miyahara,K.Hirotsu,S.Kuramitsu
Key ref: H.Ura et al. (2001). Substrate recognition mechanism of thermophilic dual-substrate enzyme. J Biochem, 130, 89-98. PubMed id: 11432784
07-Jan-99     Release date:   02-Sep-03    
Go to PROCHECK summary

Protein chains
Pfam   ArchSchema ?
Q56232  (AAT_THET8) -  Aspartate aminotransferase
385 a.a.
382 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Enzyme reactions 
   Enzyme class: E.C.  - Aspartate transaminase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: L-aspartate + 2-oxoglutarate = oxaloacetate + L-glutamate
+ 2-oxoglutarate
= oxaloacetate
+ L-glutamate
      Cofactor: Pyridoxal 5'-phosphate
Pyridoxal 5'-phosphate
Bound ligand (Het Group name = PLP) matches with 93.75% similarity
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     cytoplasm   1 term 
  Biological process     biosynthetic process   1 term 
  Biochemical function     catalytic activity     6 terms  


J Biochem 130:89-98 (2001)
PubMed id: 11432784  
Substrate recognition mechanism of thermophilic dual-substrate enzyme.
H.Ura, T.Nakai, S.I.Kawaguchi, I.Miyahara, K.Hirotsu, S.Kuramitsu.
Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for an acidic substrate. However, stepwise introduction of mutations in the active-site residues finally changed its substrate specificity to that of a dual-substrate enzyme. The final mutant, [S15D, T17V, K109S, S292R] ttAspAT, is active toward both acidic and hydrophobic substrates. During the course of stepwise mutation, the activities toward acidic and hydrophobic substrates changed independently. The introduction of a mobile Arg292* residue into ttAspAT was the key step in the change to a "dual-substrate" enzyme. The substrate recognition mechanism of this thermostable "dual-substrate" enzyme was confirmed by X-ray crystallography. This work together with previous studies on various enzymes suggest that this unique "dual-substrate recognition" mechanism is a feature of not only aminotransferases but also other enzymes.

Literature references that cite this PDB file's key reference

  PubMed id Reference
15608117 A.P.Dubnovitsky, E.G.Kapetaniou, and A.C.Papageorgiou (2005).
Enzyme adaptation to alkaline pH: atomic resolution (1.08 A) structure of phosphoserine aminotransferase from Bacillus alcalophilus.
  Protein Sci, 14, 97.
PDB codes: 1w23 1w3u
15883191 A.P.Dubnovitsky, R.B.Ravelli, A.N.Popov, and A.C.Papageorgiou (2005).
Strain relief at the active site of phosphoserine aminotransferase induced by radiation damage.
  Protein Sci, 14, 1498-1507.
PDB codes: 2bhx 2bi1 2bi2 2bi3 2bi5 2bi9 2bia 2bie 2big
15889412 K.Hirotsu, M.Goto, A.Okamoto, and I.Miyahara (2005).
Dual substrate recognition of aminotransferases.
  Chem Rec, 5, 160-172.  
14501132 S.Yoshiba, N.Nakagawa, R.Masui, T.Shibata, Y.Inoue, S.Yokoyama, and S.Kuramitsu (2003).
Overproduction, crystallization and preliminary diffraction data of ADP-ribose pyrophosphatase from Thermus thermophilus HB8.
  Acta Crystallogr D Biol Crystallogr, 59, 1840-1842.  
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