PDBsum entry 5d1h

Transferase

PDB id: 5d1h

Contents

Protein chains

204 a.a.

Waters ×10

PDB id:

5d1h

Name:

Transferase

Title:

Crystal structure of the 16s rrna (adenine(1408)-n(1))- methyltransferase w203a mutant from catenulisporales acidiphilia

Structure:

Uncharacterized protein. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Catenulispora acidiphila. Organism_taxid: 479433. Strain: dsm 44928 / nrrl b-24433 / nbrc 102108 / jcm 14897. Gene: caci_9046. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.80Å R-factor: 0.188 R-free: 0.234

Authors:

M.A.Witek,G.L.Conn

Key ref:

M.A.Witek and G.L.Conn (2016). Functional dichotomy in the 16S rRNA (m1A1408) methyltransferase family and control of catalytic activity via a novel tryptophan mediated loop reorganization. Nucleic Acids Res, 44, 342-353. PubMed id: 26609134 DOI: 10.1093/nar/gkv1306

Date:

04-Aug-15 Release date: 20-Apr-16

Protein chains

C7Q5P8  (C7Q5P8_CATAD) -  rRNA methyltransferase from Catenulispora acidiphila (strain DSM 44928 / JCM 14897 / NBRC 102108 / NRRL B-24433 / ID139908)

Seq: 250 a.a.

Struc: 204 a.a.

DOI no: 10.1093/nar/gkv1306

Nucleic Acids Res 44:342-353 (2016)

PubMed id: 26609134

Functional dichotomy in the 16S rRNA (m1A1408) methyltransferase family and control of catalytic activity via a novel tryptophan mediated loop reorganization.

M.A.Witek, G.L.Conn.

ABSTRACT

Methylation of the bacterial small ribosomal subunit (16S) rRNA on the N1 position of A1408 confers exceptionally high-level resistance to a broad spectrum of aminoglycoside antibiotics. Here, we present a detailed structural and functional analysis of the Catenulisporales acidiphilia 16S rRNA (m(1)A1408) methyltransferase ('CacKam'). The apo CacKam structure closely resembles other m(1)A1408 methyltransferases within its conserved SAM-binding fold but the region linking core β strands 6 and 7 (the 'β6/7 linker') has a unique, extended structure that partially occludes the putative 16S rRNA binding surface, and sequesters the conserved and functionally critical W203 outside of the CacKam active site. Substitution of conserved residues in the SAM binding pocket reveals a functional dichotomy in the 16S rRNA (m(1)A1408) methyltransferase family, with two apparently distinct molecular mechanisms coupling cosubstrate/ substrate binding to catalytic activity. Our results additionally suggest that CacKam exploits the W203-mediated remodeling of the β6/7 linker as a novel mechanism to control 30S substrate recognition and enzymatic turnover.