6PQB

Crystal structure of aminoglycoside-resistance methyltransferase RmtC bound to S-adenosylhomocysteine (SAH)

6PQB の概要

• エントリーDOI: 10.2210/pdb6pqb/pdb
• 関連するPDBエントリー: 3FRH 3FZG 3LCV 6CN0
• 分子名称: 16S rRNA (guanine(1405)-N(7))-methyltransferase, S-ADENOSYL-L-HOMOCYSTEINE (3 entities in total)
• 機能のキーワード: methyltransferase, ribosome, aminoglycoside resistance, s-adenosylhomocysteine, transferase
• 由来する生物種: Proteus mirabilis
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 130701.50

構造登録者

Nosrati, M.,Hoffer, E.D.,Conn, G.L. (登録日: 2019-07-08, 公開日: 2019-10-16, 最終更新日: 2023-10-11)

主引用文献

Nosrati, M.,Dey, D.,Mehrani, A.,Strassler, S.E.,Zelinskaya, N.,Hoffer, E.D.,Stagg, S.M.,Dunham, C.M.,Conn, G.L.
Functionally critical residues in the aminoglycoside resistance-associated methyltransferase RmtC play distinct roles in 30S substrate recognition.
J.Biol.Chem., 294:17642-17653, 2019

PubMed Abstract: Methylation of the small ribosome subunit rRNA in the ribosomal decoding center results in exceptionally high-level aminoglycoside resistance in bacteria. Enzymes that methylate 16S rRNA on N7 of nucleotide G1405 (mG1405) have been identified in both aminoglycoside-producing and clinically drug-resistant pathogenic bacteria. Using a fluorescence polarization 30S-binding assay and a new crystal structure of the methyltransferase RmtC at 3.14 Å resolution, here we report a structure-guided functional study of 30S substrate recognition by the aminoglycoside resistance-associated 16S rRNA (mG1405) methyltransferases. We found that the binding site for these enzymes in the 30S subunit directly overlaps with that of a second family of aminoglycoside resistance-associated 16S rRNA (mA1408) methyltransferases, suggesting that both groups of enzymes may exploit the same conserved rRNA tertiary surface for docking to the 30S. Within RmtC, we defined an N-terminal domain surface, comprising basic residues from both the N1 and N2 subdomains, that directly contributes to 30S-binding affinity. In contrast, additional residues lining a contiguous adjacent surface on the C-terminal domain were critical for 16S rRNA modification but did not directly contribute to the binding affinity. The results from our experiments define the critical features of mG1405 methyltransferase-substrate recognition and distinguish at least two distinct, functionally critical contributions of the tested enzyme residues: 30S-binding affinity and stabilizing a binding-induced 16S rRNA conformation necessary for G1405 modification. Our study sets the scene for future high-resolution structural studies of the 30S-methyltransferase complex and for potential exploitation of unique aspects of substrate recognition in future therapeutic strategies.

PubMed: 31594862
DOI: 10.1074/jbc.RA119.011181

実験手法

X-RAY DIFFRACTION (3.14 Å)