Retention of core catalytic functions by a conserved minimal ribonuclease E peptide that lacks the domain required for tetramer formation.
Ribonuclease E (RNase E) is a multifunctional endoribonuclease that has been evolutionarily conserved in both Gram-positive and Gram-negative bacteria. X-ray crystallography and biochemical studies have concluded that the Escherichia coli RNase E protein functions as a homotetramer formed by Zn linkage of dimers within a region extending from amino acid residues 416 through 529 of the 116-kDa protein. Using fragments of RNase E proteins from E. coli and Haemophilus influenzae, we show here that RNase E derivatives that are as short as 395 amino acid residues and that lack the Zn-link region shown previously to be essential for tetramer formation (i.e. amino acid residues 400-415) are catalytically active enzymes that retain the 5' to 3' scanning ability and cleavage site specificity characteristic of full-length RNase E and that also confer colony forming ability on rne null mutant bacteria. Further truncation leads to loss of these properties. Our results, which identify a minimal catalytically active RNase E sequence, indicate that contrary to current models, a tetrameric quaternary structure is not required for RNase E to carry out its core enzymatic functions.
Caruthers
Jonathan M
JM
Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA.
Feng
Yanan
Y
McKay
David B
DB
Cohen
Stanley N
SN
D020134:Catalytic Domain; D002850:Chromatography, Gel; D004722:Endoribonucleases / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D006193:Haemophilus influenzae / Q000378:metabolism; D010455:Peptides / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D015032:Zinc / Q000737:chemistry
D010455:Peptides; D004722:Endoribonucleases; C022537:ribonuclease E; D015032:Zinc