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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
2004-3-31
pubmed:abstractText
Elastin is an extracellular-matrix protein that imparts elasticity to tissues. We have used solid-state NMR to determine a number of distances and torsion angles in an elastin-mimetic peptide, (VPGVG)3, to understand the structural basis of elasticity. C-H and C-N distances between the V6 carbonyl and the V9 amide segment were measured using 13C-15N and 13C-1H rotational-echo double-resonance experiments. The results indicate the coexistence of two types of intramolecular distances: a third of the molecules have short C-H and C-N distances of 3.3 +/- 0.2 and 4.3 +/- 0.2 A, respectively, while the rest have longer distances of about 7 A. Complementing the distance constraints, we measured the (phi, psi ) torsion angles of the central pentameric unit using dipolar correlation NMR. The -angles of P7 and G8 are predominantly ~150, thus restricting the majority of the peptide to be extended. Combining all torsion angles measured for the five residues, the G8 C chemical shift, and the V6-V9 distances, we obtained a bimodal structure distribution for the PG residues in VPGVG. The minor form is a compact structure with a V6-V9 C=O-HN hydrogen bond and can be either a type II -turn or a previously unidentified turn with Pro (phi = -70, psi= 20 +/- 20) and Gly ( phi= -100 +/- 20, psi = -20 +/- 20). The major form is an extended and distorted beta-strand without a V6-V9 hydrogen bond and differs from the ideal parallel and antiparallel beta-strands. The other three residues in the VPGVG unit mainly adopt antiparallel beta-sheet torsion angles. Since (VPGVG)3 has the same 13C and 15N isotropic and anisotropic chemical shifts as the elastin-mimetic protein (VPGXG)n (X = V and K, n = 195), the observed conformational distribution around Pro and Gly sheds light on the molecular mechanism of elastin elasticity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4199-210
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Structure distribution in an elastin-mimetic peptide (VPGVG)3 investigated by solid-state NMR.
pubmed:affiliation
Department of Chemistry, Iowa State University, Ames, Iowa, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't