The isolation, structure determination, syntheses and biological activity of Nb-acetyltryptamine and three proline containing dioxopiperazines, cyclo(S-Pro-S-Leu) (2), cyclo(S-Pro-S-Ile) (3), and cyclo(S-Pro-S-Val) (4), from cultures of Rhizoctonia solani Kuhn are reported here for the first time. Despite the small amounts isolated, the absolute stereochemistry of these naturally occurring diox...

The complete amino acid sequence of human salivary statherin, a peptide which strongly inhibits precipitation from supersaturated calcium phosphate solutions, and therefore stabilizes supersaturated saliva, has been determined. The NH2-terminal half of this Mr=5380 (43 amino acids) polypeptide was determined by automated Edman degradations (liquid phase) on native statherin. The peptide was dig...

Cell biology methods have greatly influenced the elucidation of the biosynthetic pathways of apolipoproteins. In vitro and tissue culture systems allow the study, to a large extent, of the process of synthesis, intracellular processing, secretion, and extracellular processing of the major high density lipoprotein apoproteins apoA-I and A-II and also of a minor component, apoA-IV. Whereas the la...

The results of normal-mode analyses are in accord with the proposal that a low-frequency motion of the HhaI methyltransferase enzyme is responsible for base flipping in bound DNA. The vectors of the low-frequency normal mode of residues Ser-85 and Ile-86 point directly to the phosphate and ribose moieties of the DNA backbone near the target base in position to rotate the dihedral angles and fli...

Two peptides that crossreact with an antiserum raised against Phe-Met-Arg-Phe-NH2 were purified from bovine brain extract. Their structures were determined to be Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe- NH2 and Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2. The sequences were determined by gas-phase sequencing, except for the COOH-terminal phenylalaninamides. These were as...

Isoacceptors of Physarum polycephalum Ala-, Arg-, Glu-, Gln-, Gly-, Ile-, Leu-, Lys-, Ser-, Thr-, and Val-tRNAs were resolved by reverse-phase chromatography and isolated, and their codon recognition properties were determined in a ribosomal binding assay. Codon assignments were made to most isoacceptors, and they are summarized along with those determined in other studies from Escherichia coli...

Eighty-five cDNA clones for gamma-zein (proline-rich zein) from a cDNA expression library were isolated using specific antibody and cDNA probes. Nucleotide sequences of seven independent clones were determined and found to be identical in regions where they overlapped. The primary structure of the mature protein, determined from the sequence of one near full-length clone, consists of 204 amino ...

We show here that constant velocity steered molecular dynamics (SMD) simulations of alpha-helices in a vacuum present a well defined plateau in the force-extension relationship for homopolypeptides having more than (approximately) twenty residues. With the processes being far away from equilibrium, the energies strongly depend on the stretching velocity. Importantly, for a given velocity variat...

The stability of 21 amino acid conjugates of indole-3-acetic acid (IAA) toward horseradish peroxidase (HRP) was studied. The IAA conjugates of Arg, Ile, Leu, Tyr, and Val were oxidized readily by peroxidase. Those of Ala, beta-Ala, Asp, Cys, Gln, Glu, Gly, and Lys were not degraded and their recovery was above 92% after 1 hour incubation with HRP. A correlation between the stability of IAA conj...

Prolyl endopeptidases have potential for treating coeliac sprue, a disease of the intestine caused by proteolytically resistant peptides from proline-rich prolamins of wheat, barley and rye. We compared the properties of three similar bacterial prolyl endopeptidases, including the known enzymes from Flavobacterium meningosepticum (FM) and Sphingomonas capsulate (SC) and a novel enzyme from Myxo...