Proteins C-terminus

Scheme 5 Synthesis of N-Ras protein C-terminus for MIC ligation using hydiazide linker and Elhnan sulphonamide linker, (a) Cleavage of the hydrazide linker by oxidation and nucleophilic attack and Elhnan sulphonamide linker by activation and nucleophilic attack of a nucleophile, (b) Synthesis of famesylated and pahnitoylated N-Ras C-terminus with maleimido group using hydrazide linker and Ellman sulphonamide linker...

However, classical cleavage with a solution of methanol and DMAP leads to significant racemerization of cysteine. An alternative approach was to release the peptide from the solid support using H-Cys(Far)-OMe as a nucleophile with microwave irradiation for 10 min. Peptide corresponding to N-Ras protein C-terminus 13 was synthesized using Ellman sulfonamide linker strategy as shown in Scheme 5b (dotted line) [59, 60]. 

Haas, R., Jackson, B. C., Reinhold, B. and Foster, J. D. (1996) Glycoinositol phospholipid anchor and protein C-terminus of bovine erythrocyte acetylcholinesterase analysis by mass spectrometry and by protein and DNA sequencing. Biochem. J., 314, 817-25. 

After its purification and cloning (see Methods), rat BARS was revealed to have 97% and 79% identity to CtBPl and CtBP2, respectively (the transcription corepressor proteins, C-terminus-binding protein 1 and 2, that have been cloned from human and mouse Criqui-Filipe et al., 1999 Schaeper et al, 1995 Turner and Crossley, 1998) (see also Fig. 1 [Spano et al, 1999, 2006]). CtBPl and CtBP2 can themselves be considered as BARS proteins as they are also substrates of the ADP-ribosylation induced by BFA (Fig. 2). Whether this protein modification can interfere with the corepression activities of CtBPl and CtBP2 has not been directly assessed, and it is also not yet known if these proteins can induce fission. 

Knowing how the protein chain is folded is a key ingredient m understanding the mechanism by which an enzyme catalyzes a reaction Take carboxypeptidase A for exam pie This enzyme catalyzes the hydrolysis of the peptide bond at the C terminus It is... 

Critical micelle concentration (Section 19 5) Concentration above which substances such as salts of fatty acids aggre gate to form micelles in aqueous solution Crown ether (Section 16 4) A cyclic polyether that via lon-dipole attractive forces forms stable complexes with metal 10ns Such complexes along with their accompany mg anion are soluble in nonpolar solvents C terminus (Section 27 7) The amino acid at the end of a pep tide or protein chain that has its carboxyl group intact—that IS in which the carboxyl group is not part of a peptide bond Cumulated diene (Section 10 5) Diene of the type C=C=C in which a single carbon atom participates in double bonds with two others... 

Figure 2.5 Schematic illustrations of antiparallel (3 sheets. Beta sheets are the second major element of secondary structure in proteins. The (3 strands are either all antiparallel as in this figure or all parallel or mixed as illustrated in following figures, (a) The extended conformation of a (3 strand. Side chains are shown as purple circles. The orientation of the (3 strand is at right angles to those of (b) and (c). A p strand is schematically illustrated as an arrow, from N to C terminus, (bj Schematic illustration of the hydrogen bond pattern in an antiparallel p sheet. Main-chain NH and O atoms within a p sheet are hydrogen bonded to each other.

The fundamental unit of tertiary structure is the domain. A domain is defined as a polypeptide chain or a part of a polypeptide chain that can fold independently into a stable tertiary structure. Domains are also units of function. Often, the different domains of a protein are associated with different functions. For example, in the lambda repressor protein, discussed in Chapter 8, one domain at the N-terminus of the polypeptide chain binds DNA, while a second domain at the C-terminus contains a site necessary for the dimerization of two polypeptide chains to form the dimeric repressor molecule. 

The GAL4 recognition module therefore contains only one protein side chain, Lys 18, that provides specific interactions with the DNA. The remaining specific interactions with DNA are from main-chain atoms and depend critically on the correct conformation of the protein. The correct positioning of the C-terminus of the a helix is particularly important for recognition. This is to date the only example of a protein-DNA interaction in which... 

Figure 16.21 Structure of one subunit of the core protein of Slndbls virus. The protein has a similar fold to chymotrypsin and other serine proteases, comprising two Greek key motifs separated by an active site cleft. The C-terminus of the protein is bound in the catalytic site, making the coat protein inactive (Adapted from S. Lee et al., Structure 4 531-541, 1996.)...

Each precursor protein molecule is cleaved only once to generate one molecule of the coat protein, and catalytic activity is restricted to the precursor protein. Why is the coat protein itself catalytically inactive The structure of the coat protein shows that its C-terminus is bound in the active site cleft and thereby prevents other proteins entering the cleft and being cleaved. Tbis arrangement allows the precursor protein to fulfill its function to generate the coat protein and prevents the coat protein from destroying other proteins in the infected cell, including other coat proteins. 

C terminus (Section 27.7) The amino acid at the end of a peptide or protein chain that has its carboxyl group intact—that is, in which the carboxyl group is not part of a peptide bond. 

The farnesylation and subsequent processing of the Ras protein. Following farnesylation by the FTase, the carboxy-terminal VLS peptide is removed by a prenyl protein-specific endoprotease (PPSEP) in the ER, and then a prenylprotein-specific methyltransferase (PPSMT) donates a methyl group from S-adenosylmethionine (SAM) to the carboxy-terminal S-farnesylated cysteine. Einally, palmitates are added to cysteine residues near the C-terminus of the protein. 

The cDNA for this photoprotein has been cloned and expressed in E. coli, and the recombinant protein obtained was named mitrocomin (Fagan et al., 1993). Mitrocomin consists of 190 amino acid residues with a tyrosine residue at the C-terminus, and has three Ca2+-binding sites. 

The breast cancer resistance protein (BCRP) belongs to the G-branch of the ABC-transporter family (ABCG2). In contrast to most other ABC-proteins, BCRP consists of only one transmembrane domain (TDM) with one nucleotide binding fold (NBF) at its C-terminus. Because of this structural characteristic BCRP as well as other ABC-transporters with only one TMD are termed half transporters. To achieve functional activity these transporters have to form hetero- or homodimers. BCRP is involved in the multidrug resistance of certain tumors and transports endogenous compounds like cholesterol and steroid hormones. 

An exopeptidase that sequentially releases an amino from the C-terminus of a protein or peptide. Carbox-ypeptidases are classified in Enzyme Nomenclature according to catalytic type and are included in subsubclasses 3.4.16-3.4.18. 

The presence of chromosomal translocations is a consistent feature of many leukemia s, lymphomas, and certain solid tumors. At the genetic level, these events can either deregulate an intact gene by disruption or removal and replacement of the adjacent controlling elements, or create a new fusion gene that express the N-terminus of one protein fused to the C-terminus of another protein. 

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