Modomics - A Database of RNA Modifications

ID Card:

Full name: 16S rRNA (guanine(1405)-N(7))-methyltransferase
Synonym: 16S rRNA m7G1405 methyltransferase
GI: 1035502231
UniProt: Q33DX5
Structures: | 6PQB | 6CN0 |
Complex: none
Enzyme type: methyltransferase

PDB Structures:


Structure Description:


Abstract of the PDB Structure's related Publication:

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 (m 7 G1405) 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 (m 7 G1405) 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 (m 1 A1408) 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 m 7 G1405 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.

Download RCSB-PDB Structures:

Pdb Files   6CN0.pdb   6PQB.pdb  
Pdbx/mmCIF Files   6CN0.cif   6PQB.cif  

Protein sequence:



Specifically methylates the N7 position of guanine 1405 in 16S rRNA. Confers resistance to various aminoglycosides, including gentamicin and kanamycin.


Title Authors Journal Details PubMed Id DOI
RmtC introduces G1405 methylation in 16S rRNA and confers high-level aminoglycoside resistance on Gram-positive microorganisms. Jun-Ichi Wachino,Keigo Shibayama,Kouji Kimura,Kunikazu Yamane,Satowa Suzuki,Yoshichika Arakawa FEMS Microbiol Lett [details] 20722735 -
Functionally critical residues in the aminoglycoside resistance-associated methyltransferase RmtC play distinct roles in 30S substrate recognition. Meisam Nosrati,Debayan Dey,Atousa Mehrani,Sarah E Strassler,Natalia Zelinskaya,Eric D Hoffer,Scott M Stagg,Christine M Dunham,Graeme L Conn J Biol Chem [details] 31594862 -