title: New GroEL-like chaperonin of bacteriophage OBP Pseudomonas fluorescens suppresses thermal protein aggregation in an ATP-dependent manner.
abstract: Recently, we discovered and studied the first virus-encoded chaperonin of bacteriophage EL Pseudomonas aeruginosa, gene product (gp) 146. In the present study, we performed bioinformatics analysis of currently predicted GroEL-like proteins encoded by phage genomes in comparison with cellular and mitochondrial chaperonins. Putative phage chaperonins share a low similarity and do not form a monophyletic group; nevertheless, they are closer to bacterial chaperonins in the phylogenetic tree. Experimental investigation of putative GroEL-like chaperonin proteins has been continued by physicochemical and functional characterization of gp246 encoded by the genome of Pseudomonas fluorescens bacteriophage OBP. Unlike the more usual double-ring architecture of chaperonins, including the EL gp146, the recombinant gp246 produced by Escherichia coli cells has been purified as a single heptameric ring. It possesses ATPase activity and does not require a co-chaperonin for its function. In vitro experiments demonstrated that gp246 is able to suppress the thermal protein inactivation and aggregation in an ATP-dependent manner, thus indicating chaperonin function. Single-particle electron microscopy analysis revealed the different conformational states of OBP chaperonin, depending on the bound nucleotide.
authors.affiliation: Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia psemenyuk@belozersky.msu.ru.
authors.forename: Pavel I
authors.initials: PI
authors.lastname: Semenyuk
authors.affiliation: Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
authors.forename: Victor N
authors.initials: VN
authors.lastname: Orlov
authors.affiliation: Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
authors.forename: Olga S
authors.initials: OS
authors.lastname: Sokolova
authors.affiliation: Belozersky Research Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia.
authors.forename: Lidia P
authors.initials: LP
authors.lastname: Kurochkina
mesh_terms: D002151:Calorimetry; D018834:Chaperonin 60 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002942:Circular Dichroism; D003001:Cloning, Molecular; D008854:Microscopy, Electron; D011487:Protein Conformation; D017105:Pseudomonas Phages / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000821:virology*
chemical_list: D018834:Chaperonin 60
keywords: ATPase activity; bacteriophage; chaperonin; phage chaperonin; protein aggregation