Elongational flow studies on type IV collagen: comparison with type I.
Elongation flow techniques have been used to investigate the birefringent response of monodisperse type IV collagen in dilute solution and the results compared with type I collagen. A four-roll mill apparatus was used to characterize the solutions at low strain rates, epsilon < or = 300 s-1. The birefringence is nonlocalized and rises gradually to a plateau value, in accordance with rigid-rod behavior. The gradients of the tangent to the curves at zero strain rate are estimated for types IV and I collagen. The concentrations of the solutions used were in the dilute to semidilute regimes. Using a value of 300 nm for the length of type I collagen, values of 364-408 nm were calculated for the length of the type IV collagen molecule, depending on the concentration regime chosen, which is consistent with biochemical predictions based on a rigid molecule. The results imply that the behavior of type IV collagen molecules in solution is similar to type I collagen, despite the presence of several sequence interruptions in the type IV helix.
Barnard
K
K
Comparative Pathology Laboratory, School of Veterinary Science, University of Bristol, Langford, United Kingdom.
Atkins
E D
ED
Taylor
M A
MA
Gathercole
L J
LJ
D002627:Chemistry, Physical / Q000379:methods; D003094:Collagen / Q000737:chemistry*
D003094:Collagen