2C7T

CRYSTAL STRUCTURE OF THE PLP-BOUND FORM OF BTRR, A DUAL FUNCTIONAL AMINOTRANSFERASE INVOLVED IN BUTIROSIN BIOSYNTHESIS.

Summary for 2C7T

• Entry DOI: 10.2210/pdb2c7t/pdb
• Related: 2C81
• Descriptor: GLUTAMINE-2-DEOXY-SCYLLO-INOSOSE AMINOTRANSFERASE, PYRIDOXAL-5'-PHOSPHATE, SULFATE ION, ... (4 entities in total)
• Functional Keywords: aminotransferase, smat, butirosin, aminoglycoside antibiotics, transferase
• Biological source: BACILLUS CIRCULANS
• Total number of polymer chains: 1
• Total formula weight: 47428.79

Authors

Popovic, B.,Tang, X.,Chirgadze, D.Y.,Huang, F.,Blundell, T.L.,Spencer, J.B. (deposition date: 2005-11-29, release date: 2006-08-16, Last modification date: 2023-12-13)

Primary citation

Popovic, B.,Tang, X.,Chirgadze, D.Y.,Huang, F.,Blundell, T.L.,Spencer, J.B.
Crystal structures of the PLP- and PMP-bound forms of BtrR, a dual functional aminotransferase involved in butirosin biosynthesis.
Proteins, 65:220-230, 2006

PubMed Abstract: The aminotransferase (BtrR), which is involved in the biosynthesis of butirosin, a 2-deoxystreptamine (2-DOS)-containing aminoglycoside antibiotic produced by Bacillus circulans, catalyses the pyridoxal phosphate (PLP)-dependent transamination reaction both of 2-deoxy-scyllo-inosose to 2-deoxy-scyllo-inosamine and of amino-dideoxy-scyllo-inosose to 2-DOS. The high-resolution crystal structures of the PLP- and PMP-bound forms of BtrR aminotransferase from B. circulans were solved at resolutions of 2.1 A and 1.7 A with R(factor)/R(free) values of 17.4/20.6 and 19.9/21.9, respectively. BtrR has a fold characteristic of the aspartate aminotransferase family, and sequence and structure analysis categorises it as a member of SMAT (secondary metabolite aminotransferases) subfamily. It exists as a homodimer with two active sites per dimer. The active site of the BtrR protomer is located in a cleft between an alpha helical N-terminus, a central alphabetaalpha sandwich domain and an alphabeta C-terminal domain. The structures of the PLP- and PMP-bound enzymes are very similar; however BtrR-PMP lacks the covalent bond to Lys192. Furthermore, the two forms differ in the side-chain conformations of Trp92, Asp163, and Tyr342 that are likely to be important in substrate selectivity and substrate binding. This is the first three-dimensional structure of an enzyme from the butirosin biosynthesis gene cluster.

PubMed: 16894611
DOI: 10.1002/prot.21076

Experimental method

X-RAY DIFFRACTION (2.1 Å)