5KS2

RAWV_CTD (Helix form) of 16S/23S 2'-O-methyltransferase TlyA

Summary for 5KS2

• Entry DOI: 10.2210/pdb5ks2/pdb
• Related: 5EOV
• Descriptor: 16S/23S rRNA (cytidine-2'-O)-methyltransferase TlyA, CHLORIDE ION (3 entities in total)
• Functional Keywords: methyltransferase, hemolysin, ribosome, antibiotic sensitivity, transferase
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 1
• Total formula weight: 23725.49

Authors

Kuiper, E.G.,Conn, G.L. (deposition date: 2016-07-07, release date: 2017-01-04, Last modification date: 2023-10-04)

Primary citation

Witek, M.A.,Kuiper, E.G.,Minten, E.,Crispell, E.K.,Conn, G.L.
A Novel Motif for S-Adenosyl-l-methionine Binding by the Ribosomal RNA Methyltransferase TlyA from Mycobacterium tuberculosis.
J. Biol. Chem., 292:1977-1987, 2017

PubMed Abstract: Capreomycin is a potent ribosome-targeting antibiotic that is an essential component of current antituberculosis treatments, particularly in the case of multidrug-resistant Mycobacterium tuberculosis (Mtb). Optimal capreomycin binding and Mtb ribosome inhibition requires ribosomal RNA methylation in both ribosome subunits by TlyA (Rv1694), an enzyme with dual 2'-O-methytransferase and putative hemolytic activities. Despite the important role of TlyA in capreomycin sensitivity and identification of inactivating mutations in the corresponding Mtb gene tlyA, which cause resistance to capreomycin, our current structural and mechanistic understanding of TlyA action remains limited. Here, we present structural and functional analyses of Mtb TlyA interaction with its obligatory co-substrate for methyltransferase activity, S-adenosyl-l-methionine (SAM). Despite adopting a complete class I methyltransferase fold containing conserved SAM-binding and catalytic motifs, the isolated TlyA carboxyl-terminal domain exhibits no detectable affinity for SAM. Further analyses identify a tetrapeptide motif (RXWV) in the TlyA interdomain linker as indispensable for co-substrate binding. Our results also suggest that structural plasticity of the RXWV motif could contribute to TlyA domain interactions, as well as specific recognition of its two structurally distinct ribosomal RNA targets. Our findings thus reveal a novel motif requirement for SAM binding by TlyA and set the stage for future mechanistic studies of TlyA substrate recognition and modification that underpin Mtb sensitivity to capreomycin.

PubMed: 28031456
DOI: 10.1074/jbc.M116.752659

Experimental method

X-RAY DIFFRACTION (2.18 Å)