The crystal structure of hexamer RraA from Pseudomonas aeruginosa reveals six conserved protein-protein interaction sites.
RNase E functions as the rate-limiting enzyme in the global mRNA metabolism as well as in the maturation of functional RNAs. The endoribonuclease, binding to the PNPase trimer, the RhlB monomer, and the enolase dimer, assembles into an RNA degradosome necessary for effective RNA metabolism. The RNase E processing is found to be negatively regulated by the protein modulator RraA which appears to work by interacting with the non-catalytic region of the endoribonuclease and significantly reduce the interaction between RNase E and PNPase, RhlB and enolase of the RNA degradosome. Here we report the crystal structure of RraA from P. aeruginosa to a resolution of 2.0 Å. The overall architecture of RraA is very similar to other known RraAs, which are highly structurally conserved. Gel filtration and dynamic light scattering experiments suggest that the protein regulator is arranged as a hexamer, consistent with the crystal packing of "a dimer of trimer" arrangement. Structure and sequence conservation analysis suggests that the hexamer RraA contains six putative charged protein-protein interaction sites which may serve as binding sites for RNase E.
Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Chongqing Medical University, Chongqing 400016, People's Republic of China.
Jian
J
Tang
Miao
M
Luo
Siqiang
S
Niu
Hua
H
Zhou
Xuefei
X
Cai
Wenlu
W
Zhang
Yuan
Y
Hu
Yibing
Y
Yin
Ailong
A
Huang
Deqiang
D
Wang
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004722:Endoribonucleases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D011117:Polyribonucleotide Nucleotidyltransferase / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000378:metabolism; D020365:RNA Helicases / Q000378:metabolism; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism
D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D012329:RNA, Bacterial; C111244:degradosome; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C022537:ribonuclease E; D020365:RNA Helicases