1md8

<table><tr><td colspan='2'>[[1md8]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MD8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MD8 FirstGlance]. <br>

</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1gpz|1gpz]], [[1md7|1md7]]</div></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Complement_subcomponent_C1r Complement subcomponent C1r], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.41 3.4.21.41] </span></td></tr>

[[https://www.uniprot.org/uniprot/C1R_HUMAN C1R_HUMAN]] C1r B chain is a serine protease that combines with C1q and C1s to form C1, the first component of the classical pathway of the complement system.

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== Publication Abstract from PubMed ==

C1r is the serine protease (SP) that mediates autoactivation of C1, the complex that triggers the classical complement pathway. We have determined the crystal structure of two fragments from the human C1r catalytic domain, each encompassing the second complement control protein (CCP2) module and the SP domain. The wild-type species has an active structure, whereas the S637A mutant is a zymogen. The structures reveal a restricted hinge flexibility of the CCP2-SP interface, and both are characterized by the unique alpha-helical conformation of loop E. The zymogen activation domain exhibits high mobility, and the active structure shows a restricted access to most substrate binding subsites. Further implications relevant to the C1r self-activation process are derived from protein-protein interactions in the crystals.

Monomeric structures of the zymogen and active catalytic domain of complement protease c1r: further insights into the c1 activation mechanism.,Budayova-Spano M, Grabarse W, Thielens NM, Hillen H, Lacroix M, Schmidt M, Fontecilla-Camps JC, Arlaud GJ, Gaboriaud C Structure. 2002 Nov;10(11):1509-19. PMID:12429092<ref>PMID:12429092</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1md8" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Complement subcomponent C1r]]

[[Category: Human]]

[[Category: Arlaud, G J]]

[[Category: Budayova-Spano, M]]

[[Category: Fontecilla-Camps, J]]

[[Category: Gaboriaud, C]]

[[Category: Grabarse, W]]

[[Category: Hillen, H]]

[[Category: Lacroix, M]]

[[Category: Schmidt, M]]

[[Category: Thielens, N M]]

[[Category: Substrate specificity]]