Takeshi Ogita

The structures of fosfazinomycins A and B

Abstract The structures of fosfazinomycins A and B, phosphorus containing antibiotics, have been established by spectral evidence and degradation studies.

Synthesis and determination of the absolute configuration of matlystatin B

Abstract The title compound ( 1 ) was first synthesized and its absolute configuration was determined as shown in figure I.

The structure of adenomycin (C19-97 substance)

Abstract The structure of adenomycin, a new antibiotic active against Mycobacterium , has been established as a nucleoside consisting of adenine, D-ribose, (−)- chiro -inositol, L-gulosamine, L-serine and sulfate.

X-Ray crystal structure of the thallium salt of antibiotic-6016, a new polyether ionophore

The molecular structure of the antibiotic-6016 has been established by X-ray crystallographic analysis of the thallium salt, C46H77O16Tl.

Conformational analysis and docking study of potent factor XIIIa inhibitors having a cyclopropenone ring.

A conformational analysis and docking study of potent factor XIIIa inhibitors having a cyclopropenone ring were carried out in an attempt to obtain structural insight into the inhibition mechanism. First, stable conformers of the inhibitors alone were obtained from the conformational analysis by systematic search and molecular dynamics. Next, a binding form model of factor XIIIa was built based on an X-ray crystal structure of the enzyme. Finally, the docking study of the inhibitors into the models binding site was performed. From the resulting stable complex structures, it was found that the cyclopropenone ring fits the active site located at the base of the binding cavity with high complementarity. The carbonyl oxygen of the cyclopropenone ring formed a hydrogen bond to the indole NH group of Trp279 and the terminal carbon atom of the reactive C=C double bond was in close proximity to the sulfur atom of the catalytic residue, Cys314. This binding mode suggests a possible inhibition mechanism, whereby the cysteine residue reacts with the cyclopropenone ring of the inhibitor, forming an enzyme-ligand adduct. In addition, the higher interaction energies between factor XIIIa and the inhibitors alluded to the probable binding sites of the ligand side chain.

The structures of minor congeners of detoxin complex, the selective antagonist of blasticidin S1

The structures of the minor congeners of detoxin complex, viz., detoxins E1, C1, C2, C3, B1, B3 and A1 have been established on the basis of spectral and degradative evidence.

The Crystal and Molecular Structure of the Thallium Salt of Antibiotic-6016

Antibiotic-6016 is a new polyether ionophore produced by Streptomyces sp. The crystal and molecular structure of its thallium salt has been established by a three dimentional X-ray analysis using the heavy-atom method from diffractometer data. Crystals are orthorhombic, space group P212121, a = 18.767, b = 22.671, c = 12.402 A, Dm = 1.37 (flotation in aqueous KI), Dc = 1.38 g cm−3, Z = 4. The structure was refined by block-diagonal least-squares method to R = 0.056 for 3771 independent observed reflections. The antibiotic molecule contains seven ring system: three five-membered rings take an envelope conformation, while the remaining four six-membered rings adopt a chair conformation. The molecule wraps around the thallium ion. Antibiotic-6016 is the first recognized glycosidated polyether containing the hydroxyl substituent at C2 and the sugar group at the five-membered ring D.