Tetrameric Peptide

Tetrameric peptides syntheses are performed on a Symphony synthesizer (Rainin Instruments, Protein Technologies, Inc. Woburn, MA) by Fmoc solid-phase stepwise peptide synthesis on trilysine core. These instructions are easily adaptable to other automated peptide synthesis instruments. 

Tetrameric Peptide Synthesis by Convergent Strategy (Scheme 18.1)... 

Dissolve 1 pmol tetrameric peptide possessing an acetamidomethyl (Acm) protecting group in lmL of TFA/anisole (99 1). 

Linear synthesis of the tetrameric peptides is only recommended for shorter peptides, on the order of ten amino acids or less in length. We strongly prefer the synthetic route outlined Subheading 3.11. 

We strongly encourage reducing the substitution of the resin for tetrameric peptide synthesized linearly, longer molecules (>30 residues) or for peptides rich in -structural elements to a substitution value lower than 0.25mmol/g of resin. 

For monomeric peptides, the mass is confirmed by MALDI MS using ce-cyano-4-hydroxydnnamic acid as the matrix using a Voyager DE Pro instrument in reflector mode. MALDI Mass Spectra of tetrameric peptide is obtained in linear mode using sinapinic acid as matrix. 

Although biotin-fluorophores have been described in the detection of biomolecules, namely proteins, peptides, or DNA, most of these loose part of their fluorescence when binding to the tetrameric proteins avidin and streptavidin. 

A biochemical curiosity is the presence in egg white of the glycoprotein avidin.ab Each 68-kDa subunit of this tetrameric protein binds one molecule of biotin tenaciously with Kf 1015 M 1. Nature s purpose in placing this unusual protein in egg white is uncertain. Perhaps it is a storage form of biotin, but it is more likely an antibiotic that depletes the environment of biotin. A closely similar protein streptavidin is secreted into the culture medium by Streptomyces avidinii.c Its sequence is homologous to that of avidin. It has a similar binding constant for biotin and the two proteins have similar three-dimensional structures.3/d i Biotin binds at one end of a P barrel formed from antiparallel strands and is held by multiple hydrogen bonds and a conformational alteration that allows a peptide loop to close over the bound vitamin. 

Based on the natural sequence of the core domain of the Lac repressor, which tetramerizes, Fairman et al. (1996) have engineered two 21-residue peptides, Lac21E and Lac21K. In isolation, the peptides did not fold... 

Harbury et al. (1998) described a series of peptides designed to form dimeric, trimeric, and tetrameric helical bundles with right-handed supercoils. To achieve right-handed coiled coils, rather than canonical left-handed structures, an HP pattern based on an 11-residue abcdefghij repeat was used as a template. Combinations of the hydrophobic residues Ala, lie, Leu, Val, allo-Ile, and nor-Val were considered for the a, d, and h sites. The... 

Criteria for calling a compound a synthetic enzyme are (i) completion of at least one catalytic cycle (ii) its presence after the catalytic cycle in unchanged form and (iii) a saturation kinetics behavior such as is manifested by Michaelis-Menten kinetics. There is a tetrameric helical peptide that catalyzes the decarboxylation of oxaloacetate with Michaelis-Menten kinetics and accelerates the reaction 103-104-fold faster than n-butylamine as control, a record for a chemically derived artificial enzyme. 

The structure of pores formed by two synthetic leucine-serine ion channels has been investigated by Randa et al. [90]. The systems consisted of tetrameric bundles of peptides with the sequence ... 

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