Role of Ca(2+) for the mechanical properties of fibrillin.
Fibrillin-rich microfibrils are important structural elements widespread throughout connective tissues. Genetic defects identified in the Ca(2+) binding sites of fibrillin have severe effects and in addition Ca(2+) has a marked effect on the microfibrillar structure. We have studied the role of Ca(2+) on the mechanical behavior of fibrillin-rich microfibrils using the micro-needle technique. We find that Ca(2+)-depletion results in a 50% decrease in rest length and reduces the stiffness of fibrillin-rich microfibrils. At high strain, irreversible damage occurs. This behavior is consistent with Ca(2+) stabilization of interactions between consecutive EGF-like domains and breakdown in the quaternary structure upon over-extension.
Eriksen
T A
TA
Cardiff School of Biosciences, Connective Tissue Biology Laboratories, Cardiff University, Cardiff, United Kingdom. tie@kvl.dk
Wright
D M
DM
Purslow
P P
PP
Duance
V C
VC
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D004548:Elasticity; D000071837:Fibrillins; D020894:Microfibrils / Q000737:chemistry / Q000378:metabolism; D008840:Microfilament Proteins / Q000737:chemistry* / Q000378:metabolism*; D008845:Microinjections / Q000379:methods; D008958:Models, Molecular; D011480:Protease Inhibitors / Q000378:metabolism
D000071837:Fibrillins; D008840:Microfilament Proteins; D011480:Protease Inhibitors; D002118:Calcium