Arginine residues cytochrome

A number of proteins such as histones, cytochrome c and certain flagellar proteins are found to contain methylated amino acids (19). Three different methylases have been characterized and all require S-adenosylmethionine (SAM) as the methyl donor (20-23). Protein methylase I (SAM-protein arginine methyl transferase) methylates the guanidine side chain of arginine residue protein methylase II (SAM-protein carboxyl methyltransferase) transfers methyl groups only to 8- and y-carboxyl groups in the peptide chain. Carboxyl groups in the a position cannot serve as acceptors. Protein methylase III (SAM-protein lysine... 

Figure 11 Molecular model of the complex between Ru-65-c) t bs and Cc. The geometry of the complex is the same as that of the complex involving native cytochrome bs proposed by Salemme. The heme groups (red), and the ruthenimn complex (green) are highhghted. The atoms forming an electron-transfer pathway between the ruthenimn complex and the heme group of Ru-65-c) t bs are colored yellow. The lysine and arginine residues are blue, while aspartate and glutamate residues are red ...

We chose cytochrome c as the initial protein target, since it is structurally well-characterized and contains a positively charged surface made up of several lysine and arginine residues. In this study the negatively charged GlyAspGlyAsp sequence was used in the loops of 3 to complement the charge distribution on the protein, (p. 2681)... 

Fig. 21. Forehead view of reduced tuna cytochrome c, looking directly into the heme crevice. Lysine or arginine residues on the front face of the tuna cytochrome molecule are indicated by double circles. The six heavy black circles mark front-side residues which are lysine or arginine in 56 or more of the 60 known sequences of Table IX.

Shen, S. and H.W. Strobel (1993). Role of lysine and arginine residues of cytochrome P450 in the interaction between cytochrome P4502B1 and NADPH-cytochrome P450 reductase. Arch. Biochem. Biophys. 304, 257-265. 

Figure 6.2 The mechanism of cytochrome-c-peroxidase complex formation, (a) Native enzyme, (b) Activated complex with the acid-base catalytic function of distal histidine (His) and stabilization of negative charge by arginine (Arg) residue of the active site, (c) Hypothetic intermediate oxene complex, (d) Complex I after intramolecular electron regrouping of oxene complex with Fe4+ and free radical X fragment formation.

Protein (lysine) Methyltransferase. The enzyme which methylates lysine residues of proteins was named protein methylase III by Paik and Kim (210). Its recommended trivial name is protein (lysine) methyltransferase (S-adenosyl-L-methionine protein-lysine methyltransferase EC 2.1.1.25). Protein (lysine) methyltransferase was found in all rat organs examined and was localized exclusively in the nuclei. Paik and Kim (210) solubilized the enzyme from an acetone powder of calf thymus and purified it 1.3-fold. The enzyme was difficult to work with in the solubilized state, since its activity was lost on overnight storage at either — 10° or 3°C. The enzyme was most effective in methylating histones, especially arginine-rich histone. Denaturation of histone by heating at 100°C for 30 min had no effect on the rate at which protein-lysine) methyltransferase methylated it. Poly lysine and protamine were methylated at slower rates, but horse heart cytochrome c did not serve as substrate. Km for S-adenosyl-L-methionine was 3.0 X 10"6M. 

Fig. 1-19. Amino acid sequence of horse heart cytochrome c. The basic residues lysine and arginine are marked in italics and the hydrophobic residues in boldface type. Solid line arrows indicate major points of chymotryptic hydrolysis. Dashed line arrows represent minor points of chymotryptic hydrolysis. The hydrolysis observed at the peptide bonds between residues 86 and 87 and between residues 88 and 89 are not marked, since it is not certain that they were due to chymotryptic action...

Horse cytochrome c contains 21 basic residues—19 lysines and 2 arginines—and 12 acidic residues. These charges are grouped into positive and negative clusters the exact role of these charged clusters in cytochrome c interaction with the mitochondrial membrane and electron donor and acceptor is not known. 

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