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Peptide Formation (peptide + formation)
Selected AbstractsThe Possible Influence of L -Histidine on the Origin of the First Peptides on the Primordial EarthCHEMISTRY & BIODIVERSITY, Issue 6 2006Hannes Reiner Abstract One of the most unsettled problems of prebiotic evolution and the origin of life is the explanation why one enantiomeric form of biomolecules prevailed. In the experiments presented in this paper, the influence of L -histidine on the peptide formation in the Salt-Induced Peptide Formation (SIPF) reaction of the enantiomeric forms of valine, proline, serine, lysine, and tryptophan, and the catalytic effects in this first step toward the first building blocks of proteins on the primordial earth were investigated. In the majority of the produced dipeptides, a remarkable increase of yields was shown, and the preference of the L - amino acids in the peptide formation in most cases cannot be denied. In summary, our data provide further experimental evidence for the plausibility of the SIPF reaction and point at a possible important role of L -histidine in the chemical evolution on the primordial earth. [source] Peptide-dominated membranes preceding the genetic takeover by RNA: latest thinking on a classic controversyBIOESSAYS, Issue 10 2009Richard Egel Abstract It is commonly presumed that abiotic membranes were colonized by proteins later on. Yet, hydrophobic peptides could have formed primordial protein-dominated membranes on their own. In a metabolism-first context, "autocatalytically closed" sets of statistical peptides could organize a self-maintaining protometabolism, assisted by an unfolding set of ribotide-related cofactors. Pairwise complementary ribotide cofactors may have formed docking guides for stochastic peptide formation, before replicating RNA emerged from this subset. Tidally recurring wet-drying cycles and an early onset of photosynthetic activities are considered most likely to meet the thermodynamic requirements. Conceivably, the earliest peptide-dominated vesicles were engaged in light harvesting, together with isoprenoid-tethered pigments, rather than providing an external boundary. Early on, the bulk of prebiotic organic matter can have formed a contiguous layer covering the mineral sediment, held in place by colloidal coherence of a hydrogel matrix. This unconventional scenario assumes a late onset of cellular individualization , perhaps from within, resembling endosporogenesis. [source] Crystallization and preliminary crystallographic analysis of bifunctional ,-glutamylcysteine synthetase,glutatione synthetase from Streptococcus agalactiaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2009Yasunori Nakashima ,-Glutamylcysteine synthetase,glutathione synthetase (,GCS-GS) is a bifunctional enzyme that catalyzes two consecutive steps of ATP-dependent peptide formation in glutathione biosynthesis. Streptococcus agalactiae,GCS-GS is a target for the development of potential therapeutic agents. ,GCS-GS was crystallized using the sitting-drop vapour-diffusion method. The crystals grew to dimensions of 0.3 × 0.2 × 0.2,mm under reducing conditions with 5,mM TCEP. X-ray data were collected to 2.8,Å resolution from a tetragonal crystal that belonged to space group I41. [source] The Possible Influence of L -Histidine on the Origin of the First Peptides on the Primordial EarthCHEMISTRY & BIODIVERSITY, Issue 6 2006Hannes Reiner Abstract One of the most unsettled problems of prebiotic evolution and the origin of life is the explanation why one enantiomeric form of biomolecules prevailed. In the experiments presented in this paper, the influence of L -histidine on the peptide formation in the Salt-Induced Peptide Formation (SIPF) reaction of the enantiomeric forms of valine, proline, serine, lysine, and tryptophan, and the catalytic effects in this first step toward the first building blocks of proteins on the primordial earth were investigated. In the majority of the produced dipeptides, a remarkable increase of yields was shown, and the preference of the L - amino acids in the peptide formation in most cases cannot be denied. In summary, our data provide further experimental evidence for the plausibility of the SIPF reaction and point at a possible important role of L -histidine in the chemical evolution on the primordial earth. [source] | ||||||||||