3TIF

Dimeric structure of a post-hydrolysis state of the ATP-binding cassette MJ0796 bound to ADP and Pi

Summary for 3TIF

• Entry DOI: 10.2210/pdb3tif/pdb
• Related: 1L2T
• Descriptor: Uncharacterized ABC transporter ATP-binding protein MJ0796, ADENOSINE-5'-DIPHOSPHATE, HYDROGENPHOSPHATE ION, ... (6 entities in total)
• Functional Keywords: nucleotide-binding domain, abc transporter atpase, atp binding, rna binding protein
• Biological source: Methanocaldococcus jannaschii DSM 2661
• Total number of polymer chains: 2
• Total formula weight: 54708.27

Authors

Sutton, R.B. (deposition date: 2011-08-20, release date: 2012-03-21, Last modification date: 2023-09-13)

Primary citation

Zoghbi, M.E.,Fuson, K.L.,Sutton, R.B.,Altenberg, G.A.
Kinetics of the association/dissociation cycle of an ATP-binding cassette nucleotide-binding domain.
J.Biol.Chem., 287:4157-4164, 2012

PubMed Abstract: Most ATP binding cassette (ABC) proteins are pumps that transport substrates across biological membranes using the energy of ATP hydrolysis. Functional ABC proteins have two nucleotide-binding domains (NBDs) that bind and hydrolyze ATP, but the molecular mechanism of nucleotide hydrolysis is unresolved. This is due in part to the limited kinetic information on NBD association and dissociation. Here, we show dimerization of a catalytically active NBD and follow in real time the association and dissociation of NBDs from the changes in fluorescence emission of a tryptophan strategically located at the center of the dimer interface. Spectroscopic and structural studies demonstrated that the tryptophan can be used as dimerization probe, and we showed that under hydrolysis conditions (millimolar MgATP), not only the dimer dissociation rate increases, but also the dimerization rate. Neither dimer formation or dissociation are clearly favored, and the end result is a dynamic equilibrium where the concentrations of monomer and dimer are very similar. We proposed that based on their variable rates of hydrolysis, the rate-limiting step of the hydrolysis cycle may differ among full-length ABC proteins.

PubMed: 22158619
DOI: 10.1074/jbc.M111.318378

Experimental method

X-RAY DIFFRACTION (1.7995 Å)