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dc.contributor.authorBrophy, Megan Brunjes
dc.contributor.authorHayden, Joshua A.
dc.contributor.authorNolan, Elizabeth M.
dc.date.accessioned2013-11-25T17:04:03Z
dc.date.available2013-11-25T17:04:03Z
dc.date.issued2012-10
dc.date.submitted2012-08
dc.identifier.issn0002-7863
dc.identifier.issn1520-5126
dc.identifier.urihttp://hdl.handle.net/1721.1/82571
dc.description.abstractCalprotectin (CP) is an antimicrobial protein produced and released by neutrophils that inhibits the growth of pathogenic microorganisms by sequestering essential metal nutrients in the extracellular space. In this work, spectroscopic and thermodynamic metal-binding studies are presented to delineate the zinc-binding properties of CP. Unique optical absorption and EPR spectroscopic signatures for the interfacial His3Asp and His4 sites of human calprotectin are identified by using Co(II) as a spectroscopic probe. Zinc competition titrations employing chromophoric Zn(II) indicators provide a 2:1 Zn(II):CP stoichiometry, confirm that the His[subscript 3]Asp and His[subscript 4] sites of CP coordinate Zn(II), and reveal that the Zn(II) affinity of both sites is calcium-dependent. The calcium-insensitive Zn(II) competitor ZP4 affords dissociation constants of K[subscript d1] = 133 ± 58 pM and K[subscript d2] = 185 ± 219 nM for CP in the absence of Ca(II). These values decrease to K[subscript d1] ≤ 10 pM and K[subscript d2] ≤ 240 pM in the presence of excess Ca(II). The K[subscript d1] and K[subscript d2] values are assigned to the His[subscript 3]Asp and His[subscript 4] sites, respectively. In vitro antibacterial activity assays indicate that the metal-binding sites and Ca(II)-replete conditions are required for CP to inhibit the growth of both Gram-negative and -positive bacteria. Taken together, these data provide a working model whereby calprotectin responds to physiological Ca(II) gradients to become a potent Zn(II) chelator in the extracellular space.en_US
dc.description.sponsorshipNational Institutes of Health (U.S.) (Office of the Director, NIH Grant DP2OD007045)en_US
dc.description.sponsorshipSearle Scholars Programen_US
dc.description.sponsorshipMassachusetts Institute of Technology. Center for Environmental Health Sciences (NIH Grant P30-ES002109)en_US
dc.description.sponsorshipMassachusetts Institute of Technology. Dept. of Chemistryen_US
dc.language.isoen_US
dc.publisherAmerican Chemical Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1021/ja307974een_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourcePMCen_US
dc.titleCalcium Ion Gradients Modulate the Zinc Affinity and Antibacterial Activity of Human Calprotectinen_US
dc.typeArticleen_US
dc.identifier.citationBrophy, Megan Brunjes, Joshua A. Hayden, and Elizabeth M. Nolan. “Calcium Ion Gradients Modulate the Zinc Affinity and Antibacterial Activity of Human Calprotectin.” Journal of the American Chemical Society 134, no. 43 (October 31, 2012): 18089-18100.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Chemistryen_US
dc.contributor.mitauthorBrophy, Megan Brunjesen_US
dc.contributor.mitauthorHayden, Joshua A.en_US
dc.contributor.mitauthorNolan, Elizabeth M.en_US
dc.relation.journalJournal of the American Chemical Societyen_US
dc.eprint.versionAuthor's final manuscripten_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsBrophy, Megan Brunjes; Hayden, Joshua A.; Nolan, Elizabeth M.en_US
dc.identifier.orcidhttps://orcid.org/0000-0002-6153-8803
mit.licensePUBLISHER_POLICYen_US


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