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Crystal structure of Clostridium histolyticum colg collagenase PKD domain 2 at 1.6 Angstrom resolution
Structural highlights
FunctionCOLG_HATHI Clostridial collagenases are among the most efficient degraders of eukaryotic collagen known; saprophytes use collagen as a carbon source while pathogens additionally digest collagen to aid in host colonization. Has both tripeptidylcarboxypeptidase on Gly-X-Y and endopeptidase activities; the endopeptidase cuts within the triple helix region of collagen while tripeptidylcarboxypeptidase successively digests the exposed ends, thus clostridial collagenases can digest large sections of collagen (PubMed:3002446). Active on soluble type I collagen, insoluble collagen, azocoll, soluble PZ-peptide (all collagenase substrates) and gelatin (PubMed:9922257). The full-length protein has collagenase activity, while the in vivo derived C-terminally truncated shorter versions only act on gelatin (PubMed:9922257). In vitro digestion of soluble calf skin collagen fibrils requires both ColG and ColH; ColG forms missing the second collagen-binding domain are also synergistic with ColH, although their overall efficiency is decreased (PubMed:18374061, PubMed:22099748). The activator domain (residues 119-388) and catalytic subdomain (389-670) open and close around substrate using a Gly-rich hinge (387-397), allowing digestion when the protein is closed (PubMed:21947205, PubMed:23703618). Binding of collagen requires Ca(2+) and is inhibited by EGTA; the collagen-binding domain (CBD, S3a plus S3b) specifically recognizes the triple-helical conformation made by 3 collagen protein chains in the triple-helical region (PubMed:11121400). Isolated CBD (S3a plus S3b) binds collagen fibrils and sheets of many tissues (PubMed:11913772).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] Publication Abstract from PubMedClostridium histolyticum collagenases ColG and ColH are segmental enzymes that are thought to be activated by Ca(2+)-triggered domain reorientation to cause extensive tissue destruction. The collagenases consist of a collagenase module (s1), a variable number of polycystic kidney disease-like (PKD-like) domains (s2a and s2b in ColH and s2 in ColG) and a variable number of collagen-binding domains (s3 in ColH and s3a and s3b in ColG). The X-ray crystal structures of Ca(2+)-bound holo s2b (1.4 A resolution, R = 15.0%, Rfree = 19.1%) and holo s2a (1.9 A resolution, R = 16.3%, Rfree = 20.7%), as well as of Ca(2+)-free apo s2a (1.8 A resolution, R = 20.7%, Rfree = 27.2%) and two new forms of N-terminally truncated apo s2 (1.4 A resolution, R = 16.9%, Rfree = 21.2%; 1.6 A resolution, R = 16.2%, Rfree = 19.2%), are reported. The structurally similar PKD-like domains resemble the V-set Ig fold. In addition to a conserved beta-bulge, the PKD-like domains feature a second bulge that also changes the allegiance of the subsequent beta-strand. This beta-bulge and the genesis of a Ca(2+) pocket in the archaeal PKD-like domain suggest a close kinship between bacterial and archaeal PKD-like domains. Different surface properties and indications of different dynamics suggest unique roles for the PKD-like domains in ColG and in ColH. Surface aromatic residues found on ColH s2a-s2b, but not on ColG s2, may provide the weak interaction in the biphasic collagen-binding mode previously found in s2b-s3. B-factor analyses suggest that in the presence of Ca(2+) the midsection of s2 becomes more flexible but the midsections of s2a and s2b stay rigid. The different surface properties and dynamics of the domains suggest that the PKD-like domains of M9B bacterial collagenase can be grouped into either a ColG subset or a ColH subset. The conserved properties of PKD-like domains in ColG and in ColH include Ca(2+) binding. Conserved residues not only interact with Ca(2+), but also position the Ca(2+)-interacting water molecule. Ca(2+) aligns the N-terminal linker approximately parallel to the major axis of the domain. Ca(2+) binding also increases stability against heat and guanidine hydrochloride, and may improve the longevity in the extracellular matrix. The results of this study will further assist in developing collagen-targeting vehicles for various signal molecules. Structures of three polycystic kidney disease-like domains from Clostridium histolyticum collagenases ColG and ColH.,Bauer R, Janowska K, Taylor K, Jordan B, Gann S, Janowski T, Latimer EC, Matsushita O, Sakon J Acta Crystallogr D Biol Crystallogr. 2015 Mar 1;71(Pt 3):565-77. doi:, 10.1107/S1399004714027722. Epub 2015 Feb 26. PMID:25760606[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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