1q1b
Crystal structure of E. coli MalK in the nucleotide-free form
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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
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