Sweet is stable: glycosylation stabilizes collagen.
For most collagens, the melting temperature (T(m)) of the triple-helical structure of collagen correlates with the total content of proline (Pro) and 4-trans-hydroxyproline (Hyp) in the Xaa and Yaa positions of the -Gly-Xaa-Yaa- triplet repeat. The cuticle collagen of the deep-sea hydrothermal vent worm Riftia pachyptila, despite a very low content of Pro and Hyp, has a relatively high thermal stability. Rather than Hyp occupying the Yaa position, as is normally found in mammalian collagens, this position is occupied by threonine (Thr) which is O-glycosylated. We compare the triple-helix forming propensities in water of two model peptides, Ac-(Gly-Pro-Thr)(10)-NH(2) and Ac-(Gly-Pro-Thr(Galbeta))(10)-NH(2), and show that a collagen triple-helix structure is only achieved after glycosylation of Thr. Thus, we show for the first time that glycosylation is required for the formation of a stable tertiary structure and that this modification represents an alternative way of stabilizing the collagen triple-helix that is independent of the presence of Hyp.
Bann
J G
JG
Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, 3108 SW Sam Jackson Park Road, Portland, OR, USA.
Peyton
D H
DH
Bächinger
H P
HP
D000818:Animals; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism; D005690:Galactose / Q000737:chemistry; D006020:Glycopeptides / Q000737:chemistry; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009842:Oligopeptides / Q000737:chemistry; D011077:Polychaeta; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D013696:Temperature; D013912:Threonine / Q000737:chemistry / Q000378:metabolism
D006020:Glycopeptides; D009842:Oligopeptides; D013912:Threonine; D003094:Collagen; D005690:Galactose