title: E. coli HflX interacts with 50S ribosomal subunits in presence of nucleotides.
abstract: HflX is a GTP binding protein of unknown function. Based on the presence of the hflX gene in hflA operon, HflX was believed to be involved in the lytic-lysogenic decision during phage infection in Escherichia coli. We find that E. coli HflX binds 16S and 23S rRNA - the RNA components of 30S and 50S ribosomal subunits. Here, using purified ribosomal subunits, we show that HflX specifically interacts with the 50S. This finding is in line with the homology of HflX to GTPases involved in ribosome biogenesis. However, HflX-50S interaction is not limited to a specific nucleotide-bound state of the protein, and the presence of any of the nucleotides GTP/GDP/ATP/ADP is sufficient. In this respect, HflX is different from other GTPases. While E. coli HflX binds and hydrolyses both ATP and GTP, only the GTP hydrolysis activity is stimulated by 50S binding. This work uncovers interesting attributes of HflX in ribosome binding.
authors.affiliation: Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Jain
authors.forename: Neha
authors.initials: N
authors.lastname: Dhimole
authors.forename: Abu Rafay
authors.initials: AR
authors.lastname: Khan
authors.forename: Debojyoti
authors.initials: D
authors.lastname: De
authors.forename: Sushil Kumar
authors.initials: SK
authors.lastname: Tomar
authors.forename: Mathew
authors.initials: M
authors.lastname: Sajish
authors.forename: Dipak
authors.initials: D
authors.lastname: Dutta
authors.forename: Pradeep
authors.initials: P
authors.lastname: Parrack
authors.forename: Balaji
authors.initials: B
authors.lastname: Prakash
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000378:metabolism; D054681:Ribosome Subunits, Large, Bacterial / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D009711:Nucleotides; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins; C535071:HflX protein, E coli