A. Lesage et al., TRIMERIC ASSEMBLY AND 3-DIMENSIONAL STRUCTURE MODEL OF THE FACIT COLLAGEN COL1-NC1 JUNCTION FROM CD AND NMR ANALYSIS, Biochemistry, 35(30), 1996, pp. 9647-9660
The 3D structure of the COL1-NC1 junction of FACIT type XIV collagen w
as investigated using GYCDPSSCAG and (GPP)(3)GYCDPSSCAG synthetic pep
tides, circular dichroism, and NMR. At -20 degrees C and under air oxi
dation catalyzed by Cu2+, the peptide (GPP)(3)GYCDPSSCAG is able to s
elf-associate with high yield into a stable triple disulfide bonded tr
imer. The presence of a triple helical conformation was confirmed by c
ircular dichroism. The analysis of the trimer by 2D NMR provided a set
of distance constraints for the noncollagenous part. Molecular models
for the 3D structure of COL1-NC1 junction were calculated, using the
NMR distance constraints in combination with the 3D structural data re
cently established by X-ray crystallography [Bella, J., Eaten, M., Bro
dsky, B., & Berman, H. M. (1994) Science 266, 75-81] for a collagenous
triple helix. From the eight theoretically possible arrangements for
the three interchain disulfide bonds, only two close disulfide conform
ers are compatible with the experimental data. The main feature of the
trimer structure is the asymmetry of the molecule due to the disulfid
e bond pattern that induces a particular folding of one chain. This ch
ain forms a turn-like structure locked by two disulfide bonds with the
two other chains. The turn-like folding is close to that observed for
the cyclized oxidized monomeric peptide. This is the first report of
the 3D structure model for a junction between a collagenous triple hel
ical domain and a noncollagenous domain.