An Interaction between the Walker A and D-loop Motifs Is Critical to ATP Hydrolysis and Cooperativity in Bacteriophage T4 Rad50 De la Rosa, Metzere Nelson, Scott Nelson, Scott
dc.contributor.department Biochemistry, Biophysics and Molecular Biology 2018-02-17T15:06:13.000 2020-06-29T23:47:22Z 2020-06-29T23:47:22Z Sat Jan 01 00:00:00 UTC 2011 2011-07-01
dc.description.abstract <p>The ATP binding cassette (ABC) proteins make up a large superfamily with members coming from all kingdoms. The functional form of the ABC protein nucleotide binding domain (NBD) is dimeric with ATP binding sites shared between subunits. The NBD is defined by six motifs: the Walker A, Q-loop, Signature, Walker-B, D-loop, and H-loop. The D-loop contains a conserved aspartate whose function is not clear but has been proposed to be involved in cross-talk between ATP binding sites. Structures of various ABC proteins suggest an interaction between the D-loop aspartate and an asparagine residue located in Walker A loop of the opposing subunit. Here, we evaluate the functional role of the D-loop using a bacteriophage T4 ABC protein, Rad50 (gp46). Mutation of either the D-loop aspartate or the Walker A asparagine results in dramatic reductions in ATP affinity, hydrolysis rate, and cooperativity. The mutant proteins bind Mre11 (gp47) and DNA normally, but no longer support the ATP-dependent nuclease activities of Mre11. We propose that the D-loop aspartate functions to stabilize the Walker A asparagine in a position favorable for catalysis. We find that the asparagine is crucially important to the mechanism of ATP hydrolysis by increasing the affinity for ATP and positioning the γ-phosphate of ATP for catalysis. Additionally, we propose that the asparagine acts as a γ-phosphate sensor and, through its interaction with the conserved D-loop aspartate, transmits conformational changes across the dimer interface to the second ATP binding site.</p>
dc.description.comments <p>This article is from <em>Journal of Biological Chemistry</em> 286 (2011): 26258, doi:<a href="" target="_blank">10.1074/jbc.M111.256305</a>. Posted with permission. </p>
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dc.identifier archive/
dc.identifier.articleid 1079
dc.identifier.contextkey 8372727
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath bbmb_ag_pubs/66
dc.language.iso en
dc.source.bitstream archive/|||Sat Jan 15 01:25:21 UTC 2022
dc.source.uri 10.1074/jbc.M111.256305
dc.subject.disciplines Biochemistry, Biophysics, and Structural Biology
dc.subject.disciplines Molecular Biology
dc.subject.keywords DNA Enzymes
dc.subject.keywords DNA Recombination
dc.subject.keywords DNA Repair
dc.subject.keywords Enzyme Kinetics
dc.subject.keywords Enzyme Mechanisms
dc.subject.keywords ABC Protein
dc.subject.keywords DNA Exonuclease
dc.subject.keywords SMC Protein
dc.title An Interaction between the Walker A and D-loop Motifs Is Critical to ATP Hydrolysis and Cooperativity in Bacteriophage T4 Rad50
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 6570190c-e045-441a-a9bf-59c716840114
relation.isOrgUnitOfPublication c70f85ae-e0cd-4dce-96b5-4388aac08b3f
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