ET through proteins

Given that ET through proteins is fundamental to many biological processes and that H-bonds are prevalent in proteins, it is important to determine how efficiently ET can be mediated by H-bonds. Of the several studies which have been reported, that by Therien is of particular interest since it provides a comparative study of ET mediated by saturated bonds and by H-bonds.1341... 

Highly optimized ET reactions are essential for the operation of these biochemical machines. Much of the research on biological electron transfer aims to define the electronic and structural factors that regulate the rates and efficiencies of these essential transformations. This chapter will focus on studies of ET through proteins, particularly metalloproteins. ET processes involving DNA molecules have been the subject of extensive research as well, but this work is beyond the scope of this chapter. 

Activation parameters for the reaction of NO with metMb, Eq. (15), were determined in this laboratory and in collaboration with van Eldik and Stochel (Table II) (23). Comparison of these activation parameters with those determined for reactions of NO with the water soluble ferri-heme complexes Fem(TPPS)(H20)2 and Feni(TMPS)(H20)2 (Table II) demonstrate that the latter compounds represent reasonable models for the kinetics for the analogous reaction with metMb. For example, the kon step would appear to be defined largely by the H20 lability of metMb(H20), although it is clear that the diffusion through protein channels, the distal residues and the proximal histidine binding to the Fe(III) center must all influence the NO binding kinetics (23,24). These properties may indeed be reflected in the lower AS values for both the on and off reactions on metMb. In a related study, Cao et al. recently... 

Fasano, A., et al. 1995. Zonula occludens toxin modulates tight junctions through protein kinase C-dependent actin reorganization, in vitro. J Clin Invest 96 710. 

In contrast to the inhibitory actions of 5-HTi-like receptors, 5-HT2A receptors facilitate glutamate release. This facilitation may be mediated through protein kinase C activation (Arvanov et al. 1999). 

Rapacciuolo A, Suvama S, Barki-Harrington L, et al. Protein kinase A and G protein-coupled receptor kinase phosphorylation mediates P, adrenergic receptor endocytosis through different pathways. J Biol Chem 2003 278 35,403-35,411. 

Zhu WZ, Wang SQ, Chakir K, et al. Linkage of p,-adrenergic stimulation to apoptotic heart cell death through protein kinase A-independent activation of Ca2+/ calmodulin kinase II. J Clin Invest 2003 111 617-625. 

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