Amino acid side chains aliphatic

Similar ligand-ligand interactions have been reported for a large number of ternary -amino acid complexes, built up of two different amino acid.s. A compilation of 72 examples is presented in reference 39. The extra stabilisation due to ligand-ligand interactions in these complexes depends on the character of the amino-acid side chains and amounts to 0.34 - 0.57 kJ/mole for combinations of aromatic and aliphatic side chains and 0.11 - 6.3 kJ/mole when arene - arene interactions are possible. ... 

The a-helical coiled coil-based screening system already provided a wide variety of information about the interactions of fluorinated amino acids within hydrophobic and hydrophilic protein environments. Investigations on the thermal stability as well as the replicase activity have both emphasized the orthogonal properties of fluorinated aliphatic amino acid side chains. The term orthogonal in this context has been chosen by us to demonstrate that they are in fact hydrophobic... 

Volatile Products. The volatile products which result from breakdown of the polymer backbone include carbon monoxide, ammonia and acetamide, which was the major product from the aliphatic amino acids. Side-chain fragments are also found in significant yields. The presence of acetamide as the major product suggests that two related chain scission reactions coupled with elimination of the side chain must be highly favourable. 

For the mutations on the surface of the protein, the classifications based on the chemical nature of amino acids, such as hydrophobic amino acids (Ala, Cys, Phe, Gly, He, Leu, Met, Val, Trp, and Tyr), amino acid side chains that can form hydrogen bonds (Asp, Cys, Glu, His, Lys, Met, Asn, Gin, Arg, Ser, Thr, Trp, and Tyr), and so forth, improved the correlation between amino acid properties and protein mutant stability. Furthermore, the inclusion of neighboring and surrounding residues remarkably improved the correlation in all the subgroups of mutations. This result indicates that the information from nearby polar/charged amino acid residues and/or the aliphatic and aromatic residues that are close in space is important for the stability of exposed mutations. 

A typical protein chain is formed by the peptide repeating unit (—CO—NH— —C HR—) where R is an aliphatic or aromatic substituent of the amino acid and often referred to as the amino acid side chain . Most of the observed Raman bands... 

The model poly(VPGVG), whose amino acid side chains are simple aliphatic chains without further functionalization, shows an acute thermore-sponsive behavior associated to the existence of the ITT. 

In addition to the readily ionizable amino-acid side chains listed in Table 1, there are several amino-acid moieties in enzymes, which do not contain ionizable hydrogens. These include amino acids such as alanine, valine, and phenylalanine among others, that contain only carbon-hydrogen bonds in either aliphatic or aromatic side chains, and thus do not engage in proton transfer except in very unusual circumstances. Proton transfers in enzymatic reactions can also occur from co-enzymes (co-factors) which can be considered as tightly bound substrates. Typical examples of co-enzymes that are involved in proton transfer are pyridoxal phosphate and thiamine pyrophosphate. 

The vibrational spectra of reference material are introduced in Figure 3.1, which belong to the main components of soft tissue. The IR spectrum (trace A) and Raman spectrum (F) of the all-beta protein concanavalin A are shown in Figure 3.1. IR bands due to the peptide backbone with P-sheet secondary structures are found at 3284 (amide A), 1636 (amide I), 1531 (amide II), and 1235 cm-i (amide III). Bands at 1403 (COO ) and 2963, 2874, 1455 cm- (CHg) are assigned to amino acid side chains. These bands are located in the Raman spectrum at similar positions at 1398 and 1449 cm . The Raman amide I band is centered at 1672 cm , the amide III band at 1238 cm , and the weak amide II band is not observed. Instead, other Raman bands of amino acids are identified at 759 and 1555 cm for Trp 621,1003, 1031, and 1208 cm for Phe 643, 829, and 853 cm for Tyr and 1126, 1317, and 1340 cm (CH2/CH3) for aliphatic amino acids. The IR spectrum (B) and Raman spectrum (G) of the all alpha protein bovine serum albumin show a number of differences. The amide bands... 

Nonpolar Aliphatic Amino Acids Side chains... 

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