Functional Specialization of Domains Tandemly Duplicated Witin 16S rRNA Methyltransferase RsmC

Journal Article · Mon Jan 01 04:00:00 EST 2007 · Nucleic Acids Research

DOI:https://doi.org/10.1093/nar/gkm411· OSTI ID:959944

Sunita, S; Purta, E; Durawa, M; Tkaczuk, K; Swaathi, J; Bujnicki, J; Sivaraman, J

RNA methyltransferases (MTases) are important players in the biogenesis and regulation of the ribosome, the cellular machine for protein synthesis. RsmC is a MTase that catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to G1207 of 16S rRNA. Mutations of G1207 have dominant lethal phenotypes in Escherichia coli, underscoring the significance of this modified nucleotide for ribosome function. Here we report the crystal structure of E. coli RsmC refined to 2.1 Angstroms resolution, which reveals two homologous domains tandemly duplicated within a single polypeptide. We characterized the function of the individual domains and identified key residues involved in binding of rRNA and SAM, and in catalysis. We also discovered that one of the domains is important for the folding of the other. Domain duplication and subfunctionalization by complementary degeneration of redundant functions (in particular substrate binding versus catalysis) has been reported for many enzymes, including those involved in RNA metabolism. Thus, RsmC can be regarded as a model system for functional streamlining of domains accompanied by the development of dependencies concerning folding and stability.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 959944
• Report Number(s): BNL--82930-2009-JA
• Journal Information: Nucleic Acids Research, Journal Name: Nucleic Acids Research Vol. 35; ISSN 0305-1048; ISSN NARHAD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CATALYSIS
CRYSTAL STRUCTURE
ENZYMES
ESCHERICHIA COLI
METABOLISM
MUTATIONS
NUCLEOTIDES
PROTEINS
RESIDUES
RIBOSOMES
RNA
STABILITY
SUBSTRATES
SYNTHESIS
national synchrotron light source