6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) belongs to a class of catalytic enzymes involved in phosphoryl transfer and is a new target for the development of novel antimicrobial agents. In the present study, the fundamental consideration is to view the overall structure of HPPK as a network of interacting residues and to extract the most cooperative collective motions that defin...

Comparison of the crystallographic and NMR structures of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) suggests that the enzyme may undergo significant conformational change upon binding to its first substrate, ATP. Two of the three surface loops (loop 2 and loop 3) accounting for most of the conformational differences appear to be confined by crystal contacts, raising questions ab...

In many species, older males are often preferred mates because they carry "good" genes that account for their viability. In some animals, including mice, which rely heavily on chemical communication, there is some indication that an animal's age can be determined by its scent. In order to identify the attractants in aged male mouse urine, chemical and behavioral studies were performed. We herei...

Two new xanthones, 6-hydroxy-3,7-dimethoxy-8-(3-methylbut-2-enyl)-6',6'-dimethyl-5'-hydroxy-4',5'-dihydropyrano(2',3':1,2)xanthone (1) and 6-hydroxy-3,7-dimethoxy-8-(2-oxo-3-methylbut-3-enyl)-6',6'-dimethyl-5'-hydroxy-4',5'-dihydropyrano(2',3':1,2)xanthone (2), have been isolated from the stems of Cratoxylum cochinchinense (Lour.) Blume. Their structures were established on the basis of spectro...

The pH dependence and solvent isotope sensitivity of three discrete steps in the reductive half-reaction of xanthine oxidase have been investigated. The pH dependence of both kcat/Km from steady-state experiments and kred/Kdfrom rapid reaction experiments with xanthine as substrate indicate that enzyme reacts preferentially with the neutral form of substrate and that an ionizable group in the a...

The solid phase total synthesis of the marine cyanobacterial Ahp-cyclodepsipeptide Symplocamide A is reported as a model for a general route for the synthesis of tailor-made non-covalent serine protease inhibitors.