CD and NMR investigation of collagen peptides mimicking a pathological Gly-Ser mutation and a natural interruption in a similar highly charged sequence context

Abstract

Even a single Gly substitution in the triple helix domain of collagen leads to pathological conditions while natural interruptions are suggested to play important functional roles. Two peptides-one mimicking a pathological Gly-Ser substitution (ERSEQ) and the other one modeling a similar natural interruption sequence (DRSER)-are designed to facilitate the comparison for elucidating the molecular basis of their different biological roles. CD and NMR investigation of peptide ERSEQ indicates a reduction of the thermal stability and disruption of hydrogen bonding at the Ser mutation site, providing a structural basis of the OI disease resulting from the Gly-Ser mutation in the highly charged RGE environment. Both CD and NMR real-time folding results indicate that peptide ERSEQ displays a comparatively slower folding rate than peptide DRSER, suggesting that the Gly-Ser mutation may lead to a larger interference in folding than the natural interruption in a similar RSE context. Our studies suggest that unlike the rigid GPO environment, the abundant R(K)GE(D) motif may provide a more flexible sequence environment that better accommodates mutations as well as interruptions, while the electrostatic interactions contribute to its stability. These results shed insight into the molecular features of the highly charged motif and may aid the design of collagen biomimetic peptides containing important biological sites.

Recent Advances in Collagen Mimetic Peptide Structure and Design

“…100 Additionally, a natural G5G interruption, DRSER, was studied in comparison to an OI Gly → Ser substation ERSEQ. 101 In this instance, the same triple helix stability and disruption patterns were observed for both peptides. However, the Gly → Ser mutation contained a second lower stability transition in the CD thermal melting curve and had slower folding rate than the G5G interruption, suggesting a difficulty in folding encountered by the mutation but not the interruption sequence.…”

“…Notably, the major difference in these two sequences is the AA 5 position being hydrophilic (for mutation) or charged (for interruption). 101 Sequence analysis suggests that the AA 5 position in natural interruptions more frequently contain charged amino acids than Gly → Ser mutations. 101 However, the difference in these observations could be due to the naturally high propensity of Arg for the collagen triple helix compared to that of Gln.…”

“…101 Sequence analysis suggests that the AA 5 position in natural interruptions more frequently contain charged amino acids than Gly → Ser mutations. 101 However, the difference in these observations could be due to the naturally high propensity of Arg for the collagen triple helix compared to that of Gln. Notably, both these studies observe relatively high T m for all peptides, even with interruption or mutation to the Xaa-Yaa-Gly motif.…”

ADAMTSL2 gene variant in patients with features of autosomal dominant connective tissue disorders

“…Interestingly, Gly421 is predicted to be in proximity to Asn 367 (~6 Å) which is a glycosylation site. Although the mutation from a Gly to a Ser residue is a subtle change, point mutations such as this can often affect protein folding or alter functions (Chhum et al, 2016; Sun et al, 2016). As such, one could envision that the Gly421Ser mutation could alter hydrogen bond interactions, affect local secondary structure conformations and/or perturb glycan interactions thereby leading to disease causation.…”

Molecular underpinnings of integrin binding to collagen-mimetic peptides containing vascular Ehlers–Danlos syndrome–associated substitutions

“…Structural consequences of Gly substitutions in collagen triple helices have been extensively studied in the context of OI mutations to collagen I (35,(38)(39)(40)(41)(42). OI is an autosomal dominant disorder, resulting from mutations to COL1A1 or COL1A2 genes.…”