3DMW

Crystal structure of human type III collagen G982-G1023 containing C-terminal cystine knot

Summary for 3DMW

• Entry DOI: 10.2210/pdb3dmw/pdb
• Descriptor: Collagen alpha-1(III) chain (2 entities in total)
• Functional Keywords: collagen iii, cystine knot, triple helix, glycine, mad phasing, alternative splicing, disease mutation, ehlers-danlos syndrome, extracellular matrix, glycoprotein, hydroxylation, phosphoprotein, polymorphism, secreted, structural protein
• Cellular location: Secreted, extracellular space, extracellular matrix (By similarity): P02461
• Total number of polymer chains: 3
• Total formula weight: 11919.33

Authors

Boudko, S.P.,Engel, J.,Okuyama, K.,Mizuno, K.,Bachinger, H.P.,Schumacher, M.A. (deposition date: 2008-07-01, release date: 2008-09-30, Last modification date: 2021-10-20)

Primary citation

Boudko, S.P.,Engel, J.,Okuyama, K.,Mizuno, K.,Bachinger, H.P.,Schumacher, M.A.
Crystal structure of human type III collagen Gly991-Gly1032 cystine knot-containing peptide shows both 7/2 and 10/3 triple helical symmetries.
J.Biol.Chem., 283:32580-32589, 2008

PubMed Abstract: Type III collagen is a critical collagen that comprises extensible connective tissue such as skin, lung, and the vascular system. Mutations in the type III collagen gene, COL3A1, are associated with the most severe forms of Ehlers-Danlos syndrome. A characteristic feature of type III collagen is the presence of a stabilizing C-terminal cystine knot. Crystal structures of collagen triple helices reported so far contain artificial sequences like (Gly-Pro-Pro)(n) or (Gly-Pro-Hyp)(n). To gain insight into the structural properties exhibited by the natural type III collagen triple helix, we synthesized, crystallized, and determined the structure of a 12-triplet repeating peptide containing the natural type III collagen sequence from residues 991 to 1032 including the C-terminal cystine knot region, to 2.3A resolution. This represents the longest collagen triple helical structure determined to date with a native sequence. Strikingly, the Gly(991)-Gly(1032) structure reveals that the central non-imino acid-containing region adopts 10/3 superhelical properties, whereas the imino acid rich N- and C-terminal regions adhere to a 7/2 superhelical conformation. The structure is consistent with two models for the cystine knot; however, the poor density for the majority of this region suggests that multiple conformations may be adopted. The structure shows that the multiple non-imino acids make several types of direct intrahelical as well as interhelical contacts. The looser superhelical structure of the non-imino acid region of collagen triple helices combined with the extra contacts afforded by ionic and polar residues likely play a role in fibrillar assembly and interactions with other extracellular components.

PubMed: 18805790
DOI: 10.1074/jbc.M805394200

Experimental method

X-RAY DIFFRACTION (2.3 Å)