This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.

4igd

From Proteopedia

(Difference between revisions)

Jump to: navigation, search

Current revision

Crystal structure of the zymogen catalytic region of Human MASP-1

Structural highlights

4igd is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.5Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

MASP1_HUMAN Defects in MASP1 are the cause of 3MC syndrome type 1 (3MC1) [MIM:257920. 3MC1 is a disorder characterized by facial dysmorphism that includes hypertelorism, blepharophimosis, blepharoptosis and highly arched eyebrows, cleft lip and/or palate, craniosynostosis, learning disability and genital, limb and vesicorenal anomalies. The term 3MC syndrome includes Carnevale, Mingarelli, Malpuech, and Michels syndromes.^[1]

Function

MASP1_HUMAN Functions in the lectin pathway of complement, which performs a key role in innate immunity by recognizing pathogens through patterns of sugar moieties and neutralizing them. The lectin pathway is triggered upon binding of mannan-binding lectin (MBL) and ficolins to sugar moieties which leads to activation of the associated proteases MASP1 and MASP2. Functions as an endopeptidase and may activate MASP2 or C2 or directly activate C3 the key component of complement reaction. Isoform 2 may have an inhibitory effect on the activation of the lectin pathway of complement or may cleave IGFBP5.^[2] ^[3]

Publication Abstract from PubMed

Mannan-binding lectin (MBL)-associated serine proteases, MASP-1 and MASP-2, have been thought to autoactivate when MBL/ficolin.MASP complexes bind to pathogens triggering the complement lectin pathway. Autoactivation of MASPs occurs in two steps: 1) zymogen autoactivation, when one proenzyme cleaves another proenzyme molecule of the same protease, and 2) autocatalytic activation, when the activated protease cleaves its own zymogen. Using recombinant catalytic fragments, we demonstrated that a stable proenzyme MASP-1 variant (R448Q) cleaved the inactive, catalytic site Ser-to-Ala variant (S646A). The autoactivation steps of MASP-1 were separately quantified using these mutants and the wild type enzyme. Analogous mutants were made for MASP-2, and rate constants of the autoactivation steps as well as the possible cross-activation steps between MASP-1 and MASP-2 were determined. Based on the rate constants, a kinetic model of lectin pathway activation was outlined. The zymogen autoactivation rate of MASP-1 is approximately 3000-fold higher, and the autocatalytic activation of MASP-1 is about 140-fold faster than those of MASP-2. Moreover, both activated and proenzyme MASP-1 can effectively cleave proenzyme MASP-2. MASP-3, which does not autoactivate, is also cleaved by MASP-1 quite efficiently. The structure of the catalytic region of proenzyme MASP-1 R448Q was solved at 2.5 A. Proenzyme MASP-1 R448Q readily cleaves synthetic substrates, and it is inhibited by a specific canonical inhibitor developed against active MASP-1, indicating that zymogen MASP-1 fluctuates between an inactive and an active-like conformation. The determined structure provides a feasible explanation for this phenomenon. In summary, autoactivation of MASP-1 is crucial for the activation of MBL/ficolin.MASP complexes, and in the proenzymic phase zymogen MASP-1 controls the process.

Quantitative characterization of the activation steps of mannan-binding lectin (MBL)-associated serine proteases (MASPs) points to the central role of MASP-1 in the initiation of the complement lectin pathway.,Megyeri M, Harmat V, Major B, Vegh A, Balczer J, Heja D, Szilagyi K, Datz D, Pal G, Zavodszky P, Gal P, Dobo J J Biol Chem. 2013 Mar 29;288(13):8922-34. doi: 10.1074/jbc.M112.446500. Epub 2013, Feb 5. PMID:23386610^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Rooryck C, Diaz-Font A, Osborn DP, Chabchoub E, Hernandez-Hernandez V, Shamseldin H, Kenny J, Waters A, Jenkins D, Kaissi AA, Leal GF, Dallapiccola B, Carnevale F, Bitner-Glindzicz M, Lees M, Hennekam R, Stanier P, Burns AJ, Peeters H, Alkuraya FS, Beales PL. Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome. Nat Genet. 2011 Mar;43(3):197-203. doi: 10.1038/ng.757. Epub 2011 Jan 23. PMID:21258343 doi:10.1038/ng.757
↑ Dahl MR, Thiel S, Matsushita M, Fujita T, Willis AC, Christensen T, Vorup-Jensen T, Jensenius JC. MASP-3 and its association with distinct complexes of the mannan-binding lectin complement activation pathway. Immunity. 2001 Jul;15(1):127-35. PMID:11485744
↑ Moller-Kristensen M, Thiel S, Sjoholm A, Matsushita M, Jensenius JC. Cooperation between MASP-1 and MASP-2 in the generation of C3 convertase through the MBL pathway. Int Immunol. 2007 Feb;19(2):141-9. Epub 2006 Dec 20. PMID:17182967 doi:dxl131
↑ Megyeri M, Harmat V, Major B, Vegh A, Balczer J, Heja D, Szilagyi K, Datz D, Pal G, Zavodszky P, Gal P, Dobo J. Quantitative characterization of the activation steps of mannan-binding lectin (MBL)-associated serine proteases (MASPs) points to the central role of MASP-1 in the initiation of the complement lectin pathway. J Biol Chem. 2013 Mar 29;288(13):8922-34. doi: 10.1074/jbc.M112.446500. Epub 2013, Feb 5. PMID:23386610 doi:10.1074/jbc.M112.446500

1 Structural highlights
2 Disease
3 Function
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/4igd"

@@ Line 4: / Line 4: @@
 == Structural highlights ==
 <table><tr><td colspan='2'>[[4igd]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4IGD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IGD FirstGlance]. <br>
-</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr>
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5&#8491;</td></tr>
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr>
 <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4igd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4igd OCA], [https://pdbe.org/4igd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4igd RCSB], [https://www.ebi.ac.uk/pdbsum/4igd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4igd ProSAT]</span></td></tr>
 </table>

4igd

From Proteopedia

Current revision

Crystal structure of the zymogen catalytic region of Human MASP-1

Structural highlights

Disease

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

Personal tools

Navigation

Search

Toolbox