On the atomic or “local” contributions to chemical shifts due to the anisotropy of the diamagnetic susceptibility of the aromatic side chain of amino acids and of the porphyrin ring

1981 ◽  
Vol 101 (3) ◽  
pp. 921-926 ◽  
Author(s):  
C. Giessner-Prettre ◽  
B. Pullman
Keyword(s):  
Amino Acids ◽  
Diamagnetic Susceptibility ◽  
Chemical Shifts ◽  
Side Chain ◽  
Porphyrin Ring ◽  
Aromatic Side Chain

scholarly journals Pressure dependence of side chain 1H and 15N-chemical shifts in the model peptides Ac-Gly-Gly-Xxx-Ala-NH2

2020 ◽  
Vol 74 (8-9) ◽  
pp. 381-399
Author(s):  
Markus Beck Erlach ◽  
Joerg Koehler ◽  
Claudia E. Munte ◽  
Werner Kremer ◽  
Edson Crusca ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pressure Dependence ◽  
Chemical Shifts ◽  
Model Systems ◽  
Random Coil ◽  
Nonlinear Dependence ◽  
Side Chain ◽  
Unfolded Proteins ◽  
Pressure Coefficients ◽  
Compression Effects

Abstract For interpreting the pressure induced shifts of resonance lines of folded as well as unfolded proteins the availability of data from well-defined model systems is indispensable. Here, we report the pressure dependence of 1H and 15N chemical shifts of the side chain atoms in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH2 (Xxx is one of the 20 canonical amino acids) measured at 800 MHz proton frequency. As observed earlier for other nuclei the chemical shifts of the side chain nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The pressure response is described by a second degree polynomial with the pressure coefficients B1 and B2 that are dependent on the atom type and type of amino acid studied. A number of resonances could be assigned stereospecifically including the 1H and 15N resonances of the guanidine group of arginine. In addition, stereoselectively isotope labeled SAIL amino acids were used to support the stereochemical assignments. The random-coil pressure coefficients are also dependent on the neighbor in the sequence as an analysis of the data shows. For Hα and HN correction factors for different amino acids were derived. In addition, a simple correction of compression effects in thermodynamic analysis of structural transitions in proteins was derived on the basis of random-coil pressure coefficients.

scholarly journals The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

2020 ◽  
Vol 21 (22) ◽  
pp. 8776 ◽  
Author(s):  
Sailen Barik
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Structural Features ◽  
Ring Structure ◽  
Side Chain ◽  
Aromatic Side Chain ◽  
Single Ring ◽  
Energy Consuming ◽  
Animal Diet ◽  
Abundant Amino Acid

Tryptophan (Trp) holds a unique place in biology for a multitude of reasons. It is the largest of all twenty amino acids in the translational toolbox. Its side chain is indole, which is aromatic with a binuclear ring structure, whereas those of Phe, Tyr, and His are single-ring aromatics. In part due to these elaborate structural features, the biosynthetic pathway of Trp is the most complex and the most energy-consuming among all amino acids. Essential in the animal diet, Trp is also the least abundant amino acid in the cell, and one of the rarest in the proteome. In most eukaryotes, Trp is the only amino acid besides Met, which is coded for by a single codon, namely UGG. Due to the large and hydrophobic π-electron surface area, its aromatic side chain interacts with multiple other side chains in the protein, befitting its strategic locations in the protein structure. Finally, several Trp derivatives, namely tryptophylquinone, oxitriptan, serotonin, melatonin, and tryptophol, have specialized functions. Overall, Trp is a scarce and precious amino acid in the cell, such that nature uses it parsimoniously, for multiple but selective functions. Here, the various aspects of the uniqueness of Trp are presented in molecular terms.

The interaction of dimethyl sulfoxide with N-benzoyl amino acids

1981 ◽  
Vol 34 (9) ◽  
pp. 1869 ◽  
Author(s):  
CW Fong ◽  
HG Grant
Keyword(s):  
Amino Acids ◽  
Hydrogen Bonding ◽  
Dimethyl Sulfoxide ◽  
Benzene Ring ◽  
Chemical Shifts ◽  
Side Chain ◽  
Torsional Angle ◽  
Intermolecular Hydrogen Bonding ◽  
Atom Increase ◽  
Self Association

The interaction of dimethyl sulfoxide with N-benzoyl amino acids in deuterochloroform has been investigated by 13C n.m.r. spectroscopy. Examination of the chemical shifts of the benzene ring reveals that intermolecular hydrogen bonding between dimethyl sulfoxide and the amido-hydrogen atom increase the effective steric size of the amino hydrogen, resulting in an increase in the torsional angle between the benzene ring and the C(O)NHCH(R)COOH side chain. Self-association of N- benzoyl amino acids in deuterochloroform occurs largely through two COOH...O=C hydrogen bonds and does not involve intermolecular hydrogen bonding to the N-H proton.

scholarly journals Structure-activity analysis of synthetic α-thrombin-receptor-activating peptides

1993 ◽  
Vol 292 (3) ◽  
pp. 667-671 ◽  
Author(s):  
E Van Obberghen-Schilling ◽  
U B Rasmussen ◽  
V Vouret-Craviari ◽  
K U Lentes ◽  
A Pavirani ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dna Synthesis ◽  
Phospholipase C ◽  
G Protein ◽  
Receptor Activation ◽  
Human Platelets ◽  
Side Chain ◽  
Thrombin Receptor ◽  
Aromatic Side Chain ◽  
Terminal Residue

alpha-Thrombin stimulates G-protein-coupled effectors leading to secretion and aggregation in human platelets, and to a mitogenic response in CCL39 hamster fibroblasts. alpha-Thrombin receptors can be activated by synthetic peptides corresponding to the receptor sequence starting with serine-42, at the proposed cleavage site. We have previously determined that the agonist domain of receptor-activating peptides resides within the five N-terminal residues [Vouret-Craviari, Van Obberghen-Schilling, Rasmussen, Pavirani, Lecocq and Pouysségur (1992) Mol. Biol. Cell. 3, 95-102], although the 7-residue peptide (SFFLRNP) corresponding to the hamster alpha-thrombin receptor was 10 times more potent than the 5-residue peptide for activation of human platelets. In the present study we have analysed the role of individual amino acids in receptor activation by using a series of modified hexa- or hepta-peptides derived from the human alpha-thrombin-receptor sequence. Cellular events examined here include phospholipase C activation, adenylyl cyclase inhibition and DNA synthesis stimulation in non-transformed CCL39 fibroblasts and a tumorigenic variant of that line (A71 cells). Modification of the peptide sequence had similar functional consequence for each of the assays described, indicating that either a unique receptor or pharmacologically indistinguishable receptor subtypes activate distinct G-protein signalling pathways. Furthermore, we found that: (1) the N-terminal serine can be replaced by small or intermediately sized amino acids (+/- hydroxyl groups) without loss of activity. However, its replacement by an aromatic side-chain or omission of the N-terminal amino group severely reduces activity. (2) An aromatic side-chain on the penultimate N-terminal residue appears to play a critical role since phenylalanine in this position can be substituted by tyrosine without complete loss of activity whereas an alanine in its place is not tolerated. (3) Deletion of the first, second or third N-terminal residue leads to a loss of activity, suggesting that a defined spacing of more than one structural component may be important for ligand-receptor interaction. Finally, we did not observe an antagonistic effect of the inactive peptides on phospholipase C activation or DNA synthesis induced by alpha-thrombin (1 nM) or SFLLRNP (3 microM).

Conformational studies of poly(.alpha.-amino acids) with aromatic side chain effects

1968 ◽  
Vol 1 (9) ◽  
pp. 275-281 ◽  
Author(s):  
Murray Goodman ◽  
Gerald W. Davis ◽  
Ettore Benedetti
Keyword(s):  
Amino Acids ◽  
Side Chain ◽  
Aromatic Side Chain ◽  
Conformational Studies

13C nuclear magnetic resonance study of cyclodipeptides containing 13C enriched hydrophobic amino acids

1980 ◽  
Vol 45 (2) ◽  
pp. 482-490 ◽  
Author(s):  
Jaroslav Vičar ◽  
François Piriou ◽  
Pierre Fromageot ◽  
Karel Bláha ◽  
Serge Fermandjian
Keyword(s):  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constants ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Magnetic Resonance Study ◽  
Side Chain Conformation ◽  
13C Nuclear Magnetic Resonance ◽  
Hydrophobic Amino Acids

The diastereoisomeric pairs of cyclodipeptides cis- and trans-cyclo(Ala-Ala), cyclo(Ala-Phe), cyclo(Val-Val) and cyclo(Leu-Leu) containing 85% 13C enriched amino-acid residues were synthesized and their 13C-13C coupling constants were measured. The combination of 13C-13C and 1H-1H coupling constants enabled to estimate unequivocally the side chain conformation of the valine and leucine residues.

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