Amino-terminal fragment

The POMC gene is expressed in the anterior and intermediate lobes of the pituitary. The most conserved sequences between species are within the amino terminal fragment, the ACTH region, and the (3-endorphin region. POMC or related products are found in several other vertebrate tissues, including the brain, placenta, gastrointestinal tract, reproductive tract, lung, and lymphocytes. 

Soto C, Castano EM, Frangione B, Inestrosa NC. The alpha-helica to beta-strand transition in the amino-terminal fragment of the amyloid beta-peptide modulates amyloid formation. J Biol Chem 1995 270 3063-3067. 

Shen CL, Scott GL, Merchant F, Murphy RM. Light scattering analysis of fibril growth from the amino-terminal fragment beta(l-28) of beta-amyloid peptide. Biophys J 1993 65 2383-2395. 

Eysselein V, Eberlein G, Ho FJ, et al An amino-terminal fragment of cholecystokinin-58 is present in the gut evidence for a similar processing site of procholecystokinin in canine gut and brain. Reg Peptides 22 205-215, 1988 Fabre L, Vettraine J, Birkhimmer L, et al Fluvoxamine in the treatment of depression a double-blind comparison with imipramine and placebo in outpatients with major depression. Paper presented at the 18th CINP Congress, Nice, France, 1992... 

The charge on the peptide can be retained on either the carboxyl- or amino-terminal fragment, and... 

Figure 2. Httexp amino-terminal fragment sensitizes InsP3Rl to activation by InsP3 in planar lipid bilayers.

Kobayashi H, Sugino D, She MY, Ohi H, Hirashima Y, Shinohara H, et al. A bifunctional hybrid molecule of the amino-terminal fragment of urokinase and domain II of bikunin efficiently inhibits tumor cell invasion and metastasis. Eur J Biochem 1998 253 817-826. 

Thrombin cleaves apoE at residues 191 and 215 (Bradley et ai, 1982 Innerarity et al., 1983), generating a 22-kDa amino-terminal fragment and a 10-kDa carboxyl-terminal fragment. Because the two thrombolytic fragments closely approximated the two protease-resistant domains (Fig. 5), these fragments were used to model the two domains. 

About 5% of HDL and about 40 to 60% of VLDL protein are apolipoprotein C. ApoC-I is a 57-amino-acid residue polypeptide and is the smallest of the exchangeable apolipoproteins. CNBr treatment of apoC-I produced two fragments, apoC-I[l-38] and apoC-I[39-57] the amino-terminal fragment, apoC-I[l-38] had the stronger lipid affinity (Jackson et ai, 1974). In another study, the synthetic peptide apoC-I[32-57] was found to associate with phospholipid (Sparrow et al., 1977). Therefore, there appear to be at least two lipid-associating domains in apoC-I located between residues 1-31 and 32-57 (Fig. 7). The amphipathic helical domains of apoC-I are good examples of class A2 amphipathic helices. This supports experimental results showing that this protein interacts with lipid avidly. 

Amino-terminal fragments of mutant huntingtin show selective accumulation in striatal neurons and synaptic toxicity. Nature Genet 2000 25 ... 

Klee GG, Preissner CM, Schryver PG, Taylor RL, Kao PC. Multisite immunochemiluminometric assay for simultaneously measuring whole-molecule and amino-terminal fragments of human parathyrin. Clin Chem 1992 38 628-35. 

Kll. Klee, G. G., Preissner, C. M., Schryver, P. G., Taylor, R. L., and Kao, P. C., Multisite immunochemiluminometric assay for simultaneously measuring whole-molecule and Amino-Terminal fragments of human parathyrin. Clin. Chem. (Winston-Salem, N.C.) 38, 628-635... 

Hansen AP, Petros AM, Meadows RP, et al. Solution structure of the amino terminal fragment of urokinase-type plasminogen activator. Biochemistry 1994 33 4847-4864. 

The function of Factor X is to convert prothrombin to thrombin on phospholipid membranes derived from blood platelets. This proteolytic activation removes the amino-terminal fragment of prothrombin, which contains Ca" -binding sites, and releases thrombin to activate fibrinogen. Meanwhile, Factor X remains bound to the platelet membrane, where it can activate other prothrombin molecules, because during activation it retains the Ca" -binding y-carboxyglutamate residues. 

ANP and BNP are stored as prohormones in vesicles within atrial cardiomyocytes (Klein et al., 1993). Upon stimulation, proANP and proBNP are proteolytically cleaved to yield the amino-terminal fragments NTproANP and NTproBNP and the active C-terminal NP hormones ANP and BNP (Potter et al., 2006). The active hormones are secreted in equimolar amounts with their respective N-terminal fragments and bind primarily to the NP receptors NPR-A and NPR-B, which are transmembrane guanylyl cyclases. A third NP receptor, NPR-C, has no known enzymatic activity and acts to clear ANP and BNP from circulation. 

Figure 15.6. Molecular model comparison of wild-type and amino terminal fragment mutant pepsin. Superposition of the bottom -sheet and N-terminal fragment of wUd-type and N-frag mutant models. There were no major differences. Root-mean-square deviation between backbone atoms of wUd-type and N-frag was 0.28 A. The numbaa show the mutation sites in N-frag.

The level of detailed knowledge is much higher for certain repressor proteins and their interactions with DNA. The structures of four polypeptides that specifically bind to DNA have been determined recently, namely the lac repressor protein,< - > the cro repressor protein from bacteriophage, the catabolite gene activator protein from Escheria coli, and the amino-terminal fragment of the Cl repressor protein from bacteriophage In addition to the primary structure of the polypeptide, the sequence of the base pairs in that DNA fragment to which the relatively short polypeptide is bound, is known. Furthermore, structural data about the conformation of the peptide backbone are available, e.g., strands of a-helices followed by antiparallel -pleated sheets. 

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