63076-44-8Relevant articles and documents
Total synthesis of bleomycin A2 and related agents. 1. Synthesis and DNA binding properties of the extended C-terminus: Tripeptide S, tetrapeptide S, pentapeptide S, and related agents
Boger, Dale L.,Colletti, Steven L.,Honda, Takeshi,Menezes, Royce F.
, p. 5607 - 5618 (2007/10/02)
Full details of concise, diastereocontrolled syntheses of 2-5 and their incorporation into tri-, tetra-, and pentapeptide S, the C-terminus of bleomycin A2, are described. The extension of the studies to the synthesis of a complete set of tri- and tetrapeptide S structural analogs 29a,b and 43b-j is detailed, and their DNA binding constants (apparent K(B), calf thymus DNA) and apparent binding site sizes were determined. Consistent with past observations, the studies highlight the fact that the majority of the DNA binding affinity for bleomycin A2 (1.0 X 105 M-1) and deglycobleomycin A2 (1.1 x 105 M-1) is embodied within N-BOC-tripeptide S (0.26 x 105 M-1). The additional comparisons of 29a (0.18 x 105 M-1), N-BOC-tetrapeptide S (0.21 x 105 M-1), 43h (0.20 x 105 M-1), and N-BOC pentapeptide S (0.23 x 105 M-1) versus N-BOC-dipeptide S (0.10 x 105 M-1) indicate productive stabilizing binding interactions for the tripeptide S L-threonine subunit and substituent, illustrate that the entire pentanoic acid subunit of tetrapeptide S and its substituents do not significantly contribute to DNA binding affinity, and indicate that the entire β-hydroxy-L-histidine subunit of pentapeptides does not contribute to DNA binding affinity. With the exception of the L-threonine side chain substituent, the observations suggest that the tri- and tetrapeptide S substituent effects on the bleomycin A2 DNA cleavage reaction are not due to substantial stabilizing binding interactions with duplex DNA. In addition, the measured apparent binding site sizes for bleomycin A2 (3.8 base pairs), deglycobleomycin A2 (3.9 base pairs), N-BOC-tripeptide S (3.6 base pairs), N-BOC-tetrapeptide S (3.7 base pairs), 43h (3.5 base pairs), and N-BOC-pentapeptides (4.2 base pairs) versus N-BOC-dipeptide S (2.2 base pairs) and 29a (2.7 base pairs) suggest that it is the tripeptide S subunit of bleomycin A2 that is fully bound to duplex DNA, that the tripeptide S L-threonine hydroxyethyl substituent detectably affects the agent interaction with duplex DNA, but that the presence or absence of the other tetrapeptide S and pentapeptide S backbone substituents do not substantially alter the binding site size or tripeptide S binding mode.
Novel Preparation of N-Protected Amino Acid Active Esters Using 1,2,2,2-Tetrachloroethyl Carbonates
Jaoudai, Mahmoud,Martinez, Jean,Castro, Bertrand
, p. 2364 - 2367 (2007/10/02)
1,2,2,2-Tetrachloroethyl chloroformate reacts with substituted phenols or N-hydroxy imides to yield crystalline and stable mixed aryl or oximido tetrachloroethyl carbonates.When allowed to react with an N-protected amino acid derivative, these compounds proved to be efficient for the syntheses of the corresponding active esters.A series of active esters including p-nitrophenol, trichlorophenol, pentafluorophenol, and N-hydroxysuccinimide derivatives were prepared by this new procedure.
SYNTHESIS OF A HEPTAPEPTIDE WITH SEQUENCE 17 - 23 OF HUMAN CALCITONIN
Zel'tser, I. E.,Reshetnikova, I.Yu.,Borovkova, S. Yu.,Krysin, E. P.,Lavut, E. E.
, p. 449 - 456 (2007/10/02)
Two schemes for the synthesis of a peptide with sequence 17 - 23 of human calcitonin with the minimum protection of the lateral functions of the amino acids are proposed.
300-MHz 1H NMR Study of Parabactin and Its Gallium(III) Chelate
Bergeron, Raymond J.,Kline, Steven J.
, p. 3089 - 3098 (2007/10/02)
The solution structure of parabactin and its gallium(III) complex is evaluated with 300-MHz 1H NMR.The ligand is shown to exist in three separate conformers while the chelate appears to form the A cis chelate exclusively.Furthermore, the chelate is shown to exist in a 3:1 ratio of two diastereomeric forms that differ only in the disposition of the spermidine backbone.
