Proline biochemical structure

In addition to effects on biochemical reactions, the inhibitors may influence the permeability of the various cellular membranes and through physical and chemical effects may alter the structure of other subcellular structures such as proteins, nucleic acid, and spindle fibers. Unfortunately, few definite examples can be listed. The action of colchicine and podophyllin in interfering with cell division is well known. The effect of various lactones (coumarin, parasorbic acid, and protoanemonin) on mitotic activity was discussed above. Disturbances to cytoplasmic and vacuolar structure, and the morphology of mitochondria imposed by protoanemonin, were also mentioned. Interference with protein configuration and loss of biological activity was attributed to incorporation of azetidine-2-carboxylic acid into mung bean protein in place of proline. 

The structurally related myxochromides Aj.j are cyclic hexapeptides produced by several Myxococcus species. These examples contain a proline residue, which is not present in myxochromides Si 3, as the fourth amino acid in their peptide core. The NRPSs responsible for myxochromides A and S biosynthesis have exacdy the same module and domain organization thus, the fourth module of the myxochromide S synthetase must be skipped to account for the natural product. Biochemical experiments revealed that the A domain of this module activates L-proline, but the adjacent PCP domain cannot be phosphopantetheinylated by a PPTase. These results suggest that the C domain of module 5 reacts directly with the tripeptide intermediate bound to the PCP domain of module 3 in myxochromide S biosynthesis. A similar example of domain skipping has been noted in the biosynthesis of the mannopeptimycins. ... 

This chapter deals with the very important a-amino acids, the building blocks of the proteins that are necessary for the function and structure of living ceils. Enzymes, the highly specific biochemical catalysts are proteins. or-Amino acids are dipolar ions (zwitterions), RCH(N" H,)COO , as is indicated by their crystallinity, high melting point, and solubility in water rather than in nonpolar solvents. The standard (naturally occurring) amino acids are listed in Table 21-1 those marked with an asterisk are essential amino acids that cannot be synthesized in the body and so must be in the diet. They have 1° NHj s except for proline and hydroxyproline (2°). They have different R groups. 

Bause E. Structural requirements of iV-glycosylation of proteins. 43. Studies with proline peptides as conformational probes. Biochem. 

Kusano, K., M. Sakaguchi, N. Kagawa, M.R. Waterman, and T. Omura (2001). Microsomal P450s use specific proline-rich sequences for efficient folding, but not for maintenance of the folded structure. J. Biochem. (Tokyo) 129, 259-269. 

Machesky LM, Cole NB, Moss B, Pollard TD (1994b) Vaccinia virus expresses a novel profilin with a higher affinity for polyphosphoinositides than actin. Biochemistry 33 10815-10824 Mahoney NM, Janmey PA, Almo SC (1997) Structure of the profilin-poly-L-proline complex involved in morphogenesis and cytoskeletal regulation. Nat Struct Biol 4 953-960 Mammoto A, Sasaki T, Asakura T, Hotta I, Imamura H, et al (1998) Interactions of drebrin and gephyrin with profilin. Biochem Biophys Res Commun 243 86-89... 

The structural similarity of the 5-carbon amino acids, glutamic acid, ornithine, proline, and hydroxyproline, suggested interrelations in their metabolism very early to biochemical investigators. ... 

Li, S.S.C. (2005) Specificity and versatility of SH3 and other proline-recognition domains structural basis and implications for cellular signal transduction Biochem. J., Vol. 390, pp. 641-653. 

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