Linked Life Data

15784619

Source:http://linkedlifedata.com/resource/pubmed/id/15784619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2005-5-23
pubmed:databankReference
pubmed:abstractText
The collagen triple helix is characterized by the repeating sequence motif Gly-Xaa-Yaa, where Xaa and Yaa are typically proline and (2S,4R)-4-hydroxyproline (4(R)Hyp), respectively. Previous analyses have revealed that H-(Pro-4(R)Hyp-Gly)(10)-OH forms a stable triple helix, whereas H-(4(R)Hyp-Pro-Gly)(10)-OH does not. Several theories have been put forth to explain the importance of proline puckering and conformation in triple helix formation; however, the details of how they affect triple helix stability are unknown. Underscoring this, we recently demonstrated that the polypeptide Ac-(Gly-4(R)Hyp-4(R)Hyp)(10)-NH(2) forms a triple helix that is more stable than Ac-(Gly-Pro-4(R)Hyp)(10)-NH(2). Here we report crystal the structure of the H-(Gly-4(R)Hyp-4(R)Hyp)(9)-OH peptide at 1.55 A resolution. The puckering of the Yaa position 4(R)Hyp in this structure is up (Cgamma exo), as has been found in other collagen peptide structures. Notably, however, the 4(R)Hyp in the Xaa position also takes the up pucker, which is distinct from all other collagen structures. Regardless of the notable difference in the Xaa proline puckering, our structure still adopts a 7/2 superhelical symmetry similar to that observed in other collagen structures. Thus, the basis for the observed differences in the thermodynamic data of the triple helix<--> coil transition between our peptide and other triple helical peptides likely results from contributions from the unfolded state. Indeed, the unfolded state of the H-(Gly-4(R)Hyp-4(R)Hyp)(9)-OH peptide seems to be stabilized by a preformed polyproline II helix in each strand, which could be explained by the presence of a unique repeating intra-strand water-mediated bridge observed in the H-(Gly-4(R)Hyp-4(R)Hyp)(9)-OH structure, as well as a higher amount of trans peptide bonds.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
20397-403
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The crystal structure of the collagen-like polypeptide (glycyl-4(R)-hydroxyprolyl-4(R)-hydroxyprolyl)9 at 1.55 A resolution shows up-puckering of the proline ring in the Xaa position.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't