1q1b
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Crystal structure of E. coli MalK in the nucleotide-free form
OverviewOverview
The ATPase components of ATP binding cassette (ABC) transporters power the transporters by binding and hydrolyzing ATP. Major conformational changes of an ATPase are revealed by crystal structures of MalK, the ATPase subunit of the maltose transporter from Escherichia coli, in three different dimeric configurations. While other nucleotide binding domains or subunits display low affinity for each other in the absence of the transmembrane segments, the MalK dimer is stabilized through interactions of the additional C-terminal domains. In the two nucleotide-free structures, the N-terminal nucleotide binding domains are separated to differing degrees, and the dimer is maintained through contacts of the C-terminal regulatory domains. In the ATP-bound form, the nucleotide binding domains make contact and two ATPs lie buried along the dimer interface. The two nucleotide binding domains of the dimer open and close like a pair of tweezers, suggesting a regulatory mechanism for ATPase activity that may be tightly coupled to translocation.
About this StructureAbout this Structure
1Q1B is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
A tweezers-like motion of the ATP-binding cassette dimer in an ABC transport cycle., Chen J, Lu G, Lin J, Davidson AL, Quiocho FA, Mol Cell. 2003 Sep;12(3):651-61. PMID:14527411
Page seeded by OCA on Thu Feb 21 14:34:47 2008