Conformationally Constrained Dipeptide Surrogates with Aromatic Side-Chains:  Synthesis of 4-Aryl Indolizidin-9-one Amino Acids by Conjugate Addition to a Common α,ω-Diaminoazelate Enone Intermediate

2004 ◽  
Vol 69 (5) ◽  
pp. 1504-1512 ◽  
Author(s):  
Jérôme Cluzeau ◽  
William D. Lubell
Keyword(s):  
Amino Acids ◽  
Conjugate Addition ◽  
Side Chains ◽  
Conformationally Constrained ◽  
Aromatic Side Chains

Effect of thenardite on the direct detection of aromatic amino acids: implications for the search for life in the solar system

2009 ◽  
Vol 8 (4) ◽  
pp. 291-300 ◽  
Author(s):  
C. Doc Richardson ◽  
Nancy W. Hinman ◽  
Jill R. Scott
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Aromatic Amino Acids ◽  
Laser Desorption ◽  
Ionization Mechanism ◽  
Side Chains ◽  
Ion Cyclotron Resonance ◽  
Laser Desorption Mass Spectrometry ◽  
Aromatic Side Chains

AbstractWith the discovery of Na-sulphate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization in conjunction with a Fourier transform ion cyclotron resonance mass spectrometry. This technique is based on the ability of a mineral host to facilitate desorption and ionization of bio/organic molecules for detection. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali ion affinity of their aromatic side chains. In addition, substitution of the carboxyl group hydrogen by sodium led to formation of [M-H+Na]Na+ peaks. In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ attachment. Understanding how co-deposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

How can the aromatic side-chains modulate the conductance of the gramicidin channel? A new approach using non-coded amino acids

2009 ◽  
Vol 38 (3) ◽  
pp. 218-228 ◽  
Author(s):  
PASCAL DAUMAS ◽  
DRISS BENAMAR ◽  
FRÉDÉRIC HEITZ ◽  
LAURENT RANJALAHY-RASOLOARIJAO ◽  
RADOUANE MOUDEN ◽  
...  
Keyword(s):  
Amino Acids ◽  
Side Chains ◽  
New Approach ◽  
Gramicidin Channel ◽  
Aromatic Side Chains

Synthesis of conformationally constrained hydroxy-α-amino acids by intramolecular conjugate addition

Amino Acids ◽  
2000 ◽  
Vol 18 (2) ◽  
pp. 117-127 ◽  
Author(s):  
A. Avenoza ◽  
J. H. Busto ◽  
C. Cativiela ◽  
J. M. Peregrina
Keyword(s):  
Amino Acids ◽  
Conjugate Addition ◽  
Conformationally Constrained

scholarly journals Interactions between a subset of substrate side chains and AAA+ motor pore loops determine grip during protein unfolding

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Tristan A Bell ◽  
Tania A Baker ◽  
Robert T Sauer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Unfolding ◽  
Single Amino Acid ◽  
Side Chains ◽  
Substrate Side ◽  
Stable Substrate ◽  
Aromatic Side Chains

Most AAA+ remodeling motors denature proteins by pulling on the peptide termini of folded substrates, but it is not well-understood how motors produce grip when resisting a folded domain. Here, at single amino-acid resolution, we identify the determinants of grip by measuring how substrate tail sequences alter the unfolding activity of the unfoldase-protease ClpXP. The seven amino acids abutting a stable substrate domain are key, with residues 2–6 forming a core that contributes most significantly to grip. ClpX grips large hydrophobic and aromatic side chains strongly and small, polar, or charged side chains weakly. Multiple side chains interact with pore loops synergistically to strengthen grip. In combination with recent structures, our results support a mechanism in which unfolding grip is primarily mediated by non-specific van der Waal’s interactions between core side chains of the substrate tail and a subset of YVG loops at the top of the ClpX axial pore.

(η6-Arene)ruthenium(II) Labeling of Amino Acids and Peptides with Aromatic Side-Chains

1997 ◽  
Vol 130 (7) ◽  
pp. 981-988 ◽  
Author(s):  
Jens M. Wolff ◽  
William S. Sheldrick
Keyword(s):  
Amino Acids ◽  
Side Chains ◽  
Aromatic Side Chains

scholarly journals Aminopeptidase C of Aspergillus niger Is a Novel Phenylalanine Aminopeptidase

2003 ◽  
Vol 69 (2) ◽  
pp. 1246-1250 ◽  
Author(s):  
Daniëlle E. J. W. Basten ◽  
Peter J. T. Dekker ◽  
Peter J. Schaap
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspergillus Niger ◽  
Amino Acid Sequence ◽  
Aminopeptidase Activity ◽  
Side Chains ◽  
Peptide Hydrolase ◽  
Peptide Hydrolases ◽  
Aromatic Side Chains

ABSTRACT A novel enzyme with a specific phenylalanine aminopeptidase activity (ApsC) from Aspergillus niger (CBS 120.49) has been characterized. The derived amino acid sequence is not similar to any previously characterized aminopeptidase sequence but does share similarity with some mammalian acyl-peptide hydrolase sequences. ApsC was found to be most active towards phenylalanine β-naphthylamide (F-βNA) and phenylalanine para-nitroanilide (F-pNA), but it also displayed activity towards other amino acids with aromatic side chains coupled to βNA; other amino acids with nonaromatic side chains coupled to either pNA or βNA were not hydrolyzed or were poorly hydrolyzed. ApsC was not able to hydrolyze N-acetylalanine-pNA, a substrate for acyl-peptide hydrolases.

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