title: ClpL is a chaperone without auxiliary factors.
abstract: Caseinolytic protease L (ClpL) is a member of the heat shock protein (Hsp) 100 family, which is found mostly in Gram-positive bacteria. Here, ClpL, a major HSP in Streptococcus pneumoniae (pneumococcus), was biochemically characterized in vitro. Recombinant ClpL shows nucleotide hydrolase, refolding, holdase and disaggregation activity using either Mg(2+) or Mn(2+) and does not require the DnaK system for chaperone activity. ClpL exhibits two features distinct from other HSP100 family proteins: (a) Mn(2+) enhances hydrolase activity, as well as chaperone activity; and (b) NTPase activity. ClpL forms a hexamer in the presence of ADP, ATP and ATP-γ-S. Mutational analysis using double-mutant proteins mutated at the two Walker A motifs (K127A/T128A and K458A/T459A) revealed that both nucleotide-binding domains are involved in chaperone activity, ATP hydrolase activity and hexamerization. Overall, pneumococcal ClpL is a unique Mn(2+) -dependent Hsp100 family member that has chaperone activity without other co-chaperones.
authors: School of Pharmacy, Sungkyunkwan University, Suwon, Korea.
authors: Sang-Sang
authors: SS
authors: Park
authors: Hyog-Young
authors: HY
authors: Kwon
authors: Thao Dang-Hien
authors: TD
authors: Tran
authors: Moo-Hyun
authors: MH
authors: Choi
authors: Seung-Ha
authors: SH
authors: Jung
authors: Sangho
authors: S
authors: Lee
authors: David E
authors: DE
authors: Briles
authors: Dong-Kwon
authors: DK
authors: Rhee
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000737:chemistry / Q000378:metabolism*; D018832:Molecular Chaperones; D043583:Nucleoside-Triphosphatase / Q000378:metabolism*; D017510:Protein Folding; D013296:Streptococcus pneumoniae / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D008291:Malate Dehydrogenase; D008156:Luciferases; D000251:Adenosine Triphosphatases; D043583:Nucleoside-Triphosphatase
keywords: ClpL; Hsp 100 family; NTPase activity; Streptococcus pneumoniae; chaperone