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1x7o

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Crystal structure of the SpoU Methyltransferase AviRb from Streptomyces viridochromogenes

Structural highlights

1x7o is a 2 chain structure with sequence from Streptomyces viridochromogenes. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.37Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

AVRB_STRVR Specifically methylates the 2'-O-ribose position of uridine-2479 in 23S ribosomal RNA. Confers resistance to antibiotic avilamycin, an orthosomycin antibiotic.^[1] ^[2]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The emergence of antibiotic-resistant bacterial strains is a widespread problem in medical practice and drug design, and each case requires the elucidation of the underlying mechanism. AviRb from Streptomyces viridochromogenes methylates the 2'-O atom of U2479 of the 23S ribosomal RNA in Gram-positive bacteria and thus mediates resistance to the oligosaccharide (orthosomycin) antibiotic avilamycin. The structure of AviRb with and without bound cofactor S-adenosyl-L-methionine (AdoMet) was determined, showing that it is a homodimer belonging to the SpoU family within the SPOUT class of methyltransferases. The relationships within this class were analyzed in detail and, in addition, a novel fourth SpoU sequence fingerprint is proposed. Each subunit of AviRb consists of two domains. The N-terminal domain, being related to the ribosomal proteins L30 and L7Ae, is likely to bind RNA. The C-terminal domain is related to all SPOUT methyltransferases, and is responsible for AdoMet-binding, catalysis and dimerization. The cofactor binds at the characteristic knot of the polypeptide in an unusually bent conformation. The transferred methyl group points to a broad cleft formed with the L30-type domain of the other subunit. Measurements of mutant activity revealed four important residues responsible for catalysis and allowed the modeling of a complex between AviRb and the RNA target. The model includes a specificity pocket for uracil but does not contain a base for deprotonating the 2'-O atom of U2479 on methylation.

Structure and function of the antibiotic resistance-mediating methyltransferase AviRb from Streptomyces viridochromogenes.,Mosbacher TG, Bechthold A, Schulz GE J Mol Biol. 2005 Jan 21;345(3):535-45. PMID:15581897^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Weitnauer G, Gaisser S, Trefzer A, Stockert S, Westrich L, Quiros LM, Mendez C, Salas JA, Bechthold A. An ATP-binding cassette transporter and two rRNA methyltransferases are involved in resistance to avilamycin in the producer organism Streptomyces viridochromogenes Tu57. Antimicrob Agents Chemother. 2001 Mar;45(3):690-5. PMID:11181344 doi:http://dx.doi.org/10.1128/AAC.45.3.690-695.2001
↑ Treede I, Jakobsen L, Kirpekar F, Vester B, Weitnauer G, Bechthold A, Douthwaite S. The avilamycin resistance determinants AviRa and AviRb methylate 23S rRNA at the guanosine 2535 base and the uridine 2479 ribose. Mol Microbiol. 2003 Jul;49(2):309-18. PMID:12828631
↑ Mosbacher TG, Bechthold A, Schulz GE. Structure and function of the antibiotic resistance-mediating methyltransferase AviRb from Streptomyces viridochromogenes. J Mol Biol. 2005 Jan 21;345(3):535-45. PMID:15581897 doi:10.1016/j.jmb.2004.10.051