6i9a

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== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
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Skewing of the human oral microbiome causes dysbiosis and preponderance of bacteria such as Porphyromonas gingivalis, the main etiological agent of periodontitis. P. gingivalis secretes proteolytic gingipains (Kgp and RgpA/B) as zymogens inhibited by a pro-domain that is removed during extracellular activation. Unraveling the molecular mechanism of Kgp zymogenicity is essential to design inhibitors blocking its activity. Here, we found that the isolated 209-residue Kgp pro-domain is a boomerang-shaped all-beta protein similar to the RgpB pro-domain. Using composite structural information of Kgp and RgpB, we derived a plausible homology model and mechanism of Kgp-regulating zymogenicity. Accordingly, the pro-domain would laterally attach to the catalytic moiety in Kgp and block the active site through an exposed inhibitory loop. This loop features a lysine (K129) likely occupying the S1-specificity pocket and exerting latency. K129 mutation to glutamate or arginine led to misfolded protein that was degraded in vivo. Mutation to alanine gave milder effects but still strongly diminished proteolytic activity, without affecting the enzyme's subcellular location. Accordingly, the interactions of K129 within the S1 pocket are also essential for correct folding. Uniquely for gingipains, the isolated Kgp pro-domain dimerized through an interface, which partially overlapped with that between the catalytic moiety and the pro-domain within the zymogen, i.e. both complexes are mutually exclusive. Thus, pro-domain dimerization, together with partial rearrangement of the active site upon activation, explain the lack of inhibition of the pro-domain in trans. Our results reveal that the specific latency mechanism of Kgp differs from those of Rgps.
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Porphyromonas gingivalis is a member of the dysbiotic oral microbiome and a "keystone pathogen" that causes severe periodontal disease, which is among the most prevalent infectious diseases. Part of the virulence factors secreted by P. gingivalis are the essential cysteine peptidases gingipain K (Kgp) and R (RgpA and RgpB), which account for 85% of the extracellular proteolytic activity of the pathogen and are thus prime targets for inhibition. We report the high-resolution (1.20 A) complex structure of Kgp with KYT-36, a peptide-derived, potent, bioavailable and highly selective inhibitor, which is widely used for studies in vitro, in cells and in vivo. Sub-nanomolar inhibition of Kgp is achieved by tight binding to the active-site cleft, which is covered for its sub-sites S3 through S1' under establishment of nine hydrophobic interactions, 14 hydrogen bonds and one salt bridge. In addition, an inhibitor carbonyl carbon that mimics the scissile carbonyl of substrates is pyramidalized and just 2.02 A away from the catalytic nucleophile of Kgp, C(477)Sgamma. Thus, the crystal structure emulates a reaction intermediate of the first nucleophilic attack during catalysis of cysteine peptidases. The present study sets the pace for the development of tailored next-generation drugs to tackle P. gingivalis.
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Structural insights unravel the zymogenic mechanism of the virulence factor gingipain K from Porphyromonas gingivalis, a causative agent of gum disease from the human oral microbiome.,Pomowski A, Uson I, Nowakowska ZM, Veillard F, Sztukowska MN, Guevara T, Goulas T, Mizgalska D, Nowak ML, Potempa BA, Huntington JA, Potempa J, Gomis-Ruth FX J Biol Chem. 2017 Feb 14. pii: jbc.M117.776724. doi: 10.1074/jbc.M117.776724. PMID:28196869<ref>PMID:28196869</ref>
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Structural determinants of inhibition of Porphyromonas gingivalis gingipain K by KYT-36, a potent, selective, and bioavailable peptidase inhibitor.,Guevara T, Rodriguez-Banqueri A, Lasica AM, Ksiazek M, Potempa BA, Potempa J, Gomis-Ruth FX Sci Rep. 2019 Mar 20;9(1):4935. doi: 10.1038/s41598-019-41354-3. PMID:30894633<ref>PMID:30894633</ref>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

Revision as of 08:18, 3 April 2019

Porphyromonas gingivalis gingipain K (Kgp) in complex with inhibitor KYT-36

PDB ID 6i9a

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