Crystal structures of the Chromobacterium violaceumω-transaminase reveal major structural rearrangements upon binding of coenzyme PLP.
Author
Summary, in English
SUMMARY: The bacterial ω-transaminase from Chromobacterium violaceum (Cv-ωTA, EC 2.6.1.18) catalyzes industrially important transamination reactions by use of the coenzyme pyridoxal 5'-phosphate (PLP). Here, we present four crystal structures of Cv-ωTA: two in the apo form, one in the holo form and one in an intermediate state, at resolutions between 1.35 and 2.4 Å. The enzyme is a homodimer with a molecular weight of approximately 100 kDa. Each monomer has an active site at the dimeric interface that involves amino acid residues from both subunits. The apo-Cv-ωTA structure reveals unique "relaxed" conformations of three critical loops involved in structuring the active site, that have not previously been seen in a transaminase. Analysis of the four crystal structures reveals major structural rearrangements involving elements of the large and small domains of both monomers that reorganize the active site in the presence of PLP. The conformational change appears to be triggered by binding of the phosphate group of PLP. Furthermore, one of the apo structures shows a disordered "roof" over the PLP binding site, while in the other apo form and the holo form the "roof" is ordered. Comparison with other known transaminase crystal structures suggests that ordering of the "roof" structure may be associated with substrate binding in Cv-ωTA and some other transaminases. STRUCTURED DIGITAL ABSTRACT: -transaminases and -transaminases bind by dynamic light scattering (View interaction) -transaminase and -transaminase bind by x-ray crystallography (View interaction) -transaminase and -transaminase bind by x-ray crystallography (View interaction).
Department/s
Publishing year
2012
Language
English
Pages
779-792
Publication/Series
The FEBS Journal
Volume
279
Issue
5
Links
Document type
Journal article
Publisher
Wiley-Blackwell
Topic
- Biochemistry and Molecular Biology
Keywords
- pyridoxal 5'-phosphate (PLP)
- phosphate cup
- cofactor binding
- 3D structure
- class I transaminase
Status
Published
ISBN/ISSN/Other
- ISSN: 1742-464X