title: Genetic selection designed to stabilize proteins uncovers a chaperone called Spy.
abstract: To optimize the in vivo folding of proteins, we linked protein stability to antibiotic resistance, thereby forcing bacteria to effectively fold and stabilize proteins. When we challenged Escherichia coli to stabilize a very unstable periplasmic protein, it massively overproduced a periplasmic protein called Spy, which increases the steady-state levels of a set of unstable protein mutants up to 700-fold. In vitro studies demonstrate that the Spy protein is an effective ATP-independent chaperone that suppresses protein aggregation and aids protein refolding. Our strategy opens up new routes for chaperone discovery and the custom tailoring of the in vivo folding environment. Spy forms thin, apparently flexible cradle-shaped dimers. The structure of Spy is unlike that of any previously solved chaperone, making it the prototypical member of a new class of small chaperones that facilitate protein refolding in the absence of energy cofactors.
authors.affiliation: Howard Hughes Medical Institute, Chevy Chase, MD, USA.
authors.forename: Shu
authors.initials: S
authors.lastname: Quan
authors.forename: Philipp
authors.initials: P
authors.lastname: Koldewey
authors.forename: Tim
authors.initials: T
authors.lastname: Tapley
authors.forename: Nadine
authors.initials: N
authors.lastname: Kirsch
authors.forename: Karen M
authors.initials: KM
authors.lastname: Ruane
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pfizenmaier
authors.forename: Rong
authors.initials: R
authors.lastname: Shi
authors.forename: Stephan
authors.initials: S
authors.lastname: Hofmann
authors.forename: Linda
authors.initials: L
authors.lastname: Foit
authors.forename: Guoping
authors.initials: G
authors.lastname: Ren
authors.forename: Ursula
authors.initials: U
authors.lastname: Jakob
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Xu
authors.forename: Miroslaw
authors.initials: M
authors.lastname: Cygler
authors.forename: James C A
authors.initials: JC
authors.lastname: Bardwell
mesh_terms: D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015202:Protein Engineering; D017510:Protein Folding; D055503:Protein Multimerization; D055550:Protein Stability; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013634:Tannins / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D033903:Periplasmic Proteins; D011993:Recombinant Fusion Proteins; C104888:Spy protein, E coli; D013634:Tannins