title: Nucleotide-induced conformational changes of tetradecameric GroEL mapped by H/D exchange monitored by FT-ICR mass spectrometry.
abstract: Here we employ hydrogen/deuterium exchange mass spectrometry (HDX-MS) to access E. coli chaperonin GroEL conformation. The ~800 kDa tetradecameric GroEL plays an essential role in the proper folding of many proteins. Previous studies of the structural dynamics of GroEL upon ATP binding have been inconsistent, showing either minimal or major allosteric changes. Our results, based on the native, non-mutated, protein under physiological conditions in solution demonstrate substantial changes in conformation and/or flexibility upon ATP binding. We capture the pivotal step in its functional cycle by use of a non-hydrolyzable ATP analog, ATPγS, to mimic the ATP-bound GroEL state. Comparison of HDX-MS results for apo GroEL and GroEL-ATPγS enables the characterization of the nucleotide-regulated conformational changes throughout the entire protein with high sequence resolution. The 14-mer GroEL complex is the largest protein assembly yet accessed by HDX-MS, with sequence resolution of segments of as few as five amino acids.
authors: Florida State University, Department of Chemistry, Tallahassee, FL 32306, USA.
authors: Qian
authors: Q
authors: Zhang
authors: Jin
authors: J
authors: Chen
authors: Kunihiro
authors: K
authors: Kuwajima
authors: Hui-Min
authors: HM
authors: Zhang
authors: Feng
authors: F
authors: Xian
authors: Nicolas L
authors: NL
authors: Young
authors: Alan G
authors: AG
authors: Marshall
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D018834:Chaperonin 60 / Q000737:chemistry* / Q000378:metabolism; D041961:Deuterium Exchange Measurement; D004926:Escherichia coli / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: D018834:Chaperonin 60; D000255:Adenosine Triphosphate