Conservation during evolution

As to be expected from a peptide that has been highly conserved during evolution, NPY has many effects, e.g. in the central and peripheral nervous system, in the cardiovascular, metabolic and reproductive system. Central effects include a potent stimulation of food intake and appetite control [2], anxiolytic effects, anti-seizure activity and various forms of neuroendocrine modulation. In the central and peripheral nervous system NPY receptors (mostly Y2 subtype) mediate prejunctional inhibition of neurotransmitter release. In the periphery NPY is a potent direct vasoconstrictor, and it potentiates vasoconstriction by other agents (mostly via Yi receptors) despite reductions of renal blood flow, NPY enhances diuresis and natriuresis. NPY can inhibit pancreatic insulin release and inhibit lipolysis in adipocytes. It also can regulate gut motility and gastrointestinal and renal epithelial secretion. 

This essay was written in an attempt to explain our overview of primary cell walls and to reach consensus on the nomenclature of primary cell wall polysaccharides. We present evidence supporting the hypothesis that cellulose, xyloglucan, arabinoxylan, homogalacturonan, RG-I, and RG-II are the six polysaccharides common to all primary cell walls of higher plants. In many cells, these six polysaccharides account for all or nearly all of the primary wall polysaccharides. Like the physically interacting proteins that constitute the electron transport machinery of mitochondria, the structures of the six patently ubiquitous polysaccharides of primary cell walls have been conserved during evolution. Indeed, we hypothesize that the common set of six structural polysaccharides of primary cell walls have been structurally... 

The paired box is another sequence motif that is very well conserved during evolution and is found in a number of genes known to be of developmental significance in lower organisms. The paired box encodes the 128-amino acid paired domain, which binds DNA(Chalapakis et al., 1991), and shows similarity, with a helix-tum-helix motif, to the homeodomain. 

The three major MAPK families, whose regulation and function have been conserved during evolution in eukaryotic cells, are extracellular... 

All cells have specific and highly sensitive signal-transducing mechanisms, which have been conserved during evolution. 

Of the two, classic ones are far less common however, those that do exist are frequently found at the loop end of 3-hairpinsJ81 Inverse y-tums generally do not lead to peptide chain reversal and are frequently situated at either the end of a-helices or within strands of p-sheets or adjacent to certain loop motifs. 91 They are generally well conserved during evolution and some are found at key positions within proteins. 

The amino acid sequences of the cyclophilins remained highly conserved during evolution. This holds in particular for the proteins from eukaryotes. The cyclophilins from bovine thymus and from porcine kidney are identical in sequence (Takahashi et al., 1989), and the human and the bovine cyclophilins share 98% identical amino acids (Haendler et al., 1987). The homology between the mammalian cyclophilins and the cytosolic PPl from E. coli is about 25% (Hayano et al., 1991). The PPIs from porcine kidney and E. coli cytoplasm were used in most of the work on the function of prolyl isomerases as catalysts of protein folding that will be discussed herein. 

The presence of similar insect sulfakinins in species as diverse as cockroaches and Drosophila suggests this peptide family may be widely distributed among the Insecta. In addition, the C-terminal octapeptide core appears to have been conserved during evolution. 

Weaver et al. (1985) noted some similarities in the active site of the three lysozymes, but with the following striking difference. Residue 73 (Glu) in goose corresponds with residue 35 (Glu) in chick and with residue 11 (Glu) in bacteriophage T4. On the other hand, there are two Asp residues at positions 86 and 97 in the goose active site, neither of which corresponds exactly with Asp-52 of chick nor Asp-20 of T4. The implications for potential differences in the mechanism of catalytic action by the three lysozymes were discussed by Johnson et al. (1988) and by et al. (1985). The latter authors discussed the unresolved question as to whether the c-type lysozyme exons correspond to distinct structural and/or functional entities that are conserved during evolution of the three types of lysozyme considered. 

The Zeeman quantum number q is conserved during evolution under a high field Hamiltonian. Thus neglecting relaxation... 

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