Dynamic Behavior of Vitronectin at the Cell-Material Interface.

Considering that vitronectin (VN) can promote both cell adhesion and matrix degradation, it is likely to play a dual role at the cell-biomaterial interface. In this paper we therefore describe details of the dynamic interplay between matrix adhesion and pericellular proteolysis in endothelial cells adhered to glass model substratum. Initially we show that coating concentration determines protein organization at the surface.

Plastocyanin microheterogeneity in Scenedesmus acutus MT8.

Two total plastocyanin (PC) fractions - loosely bound (lPC) and strongly bound (sPC) were extracted (84% and 16%, respectively) from the homogenate of Scenedesmus acutus MT8. Two-fold isolation-purification procedure including DE-52 chromatography separated IPC into a smaller oxidized [IPC (II)] and a larger reduced [IPC(I)] fractions, in contrast to sPC, where sPC(ll) greatly dominated over sPC(I). Analytical isoelectric focusing (IEF) separated IPC(II) into two main fractions only in the presence of 8 M urea, implying microheterogeneity.

Comparative study of the stability of poplar plastocyanin isoforms.

The stability of the two isoforms of poplar plastocyanin (PCa and PCb) was studied with differential scanning calorimetry (DSC) technique. It was shown that the thermal unfolding of both isoforms is an irreversible process with two endothermic and one exothermic peaks. The melting temperature of PCb was found to be 1.

Experimental and numerical study of the poplar plastocyanin isoforms using Tyr as a probe for electrostatic similarity and dissimilarity.

A detailed study of the tyrosine spectral characteristics was carried out in a broad range of pHs for both isoforms of plastocyanin from poplar. It was found that Tyr 80 is always protonated while Tyr 83 can form a tirosinate at high pHs. The pK(a) of Tyr 83 is practically identical in plastocyanin a and b, but the quenching of its spectrum is different in the isoforms.