Molecular motions are widely regarded as contributing factors in many aspects of protein function. The enzyme dihydrofolate reductase (DHFR), and particularly that from Escherichia coli, has become an important system for investigating the linkage between protein dynamics and catalytic function, both because of the location and timescales of the motions observed and because of the availability ...

Most macromolecular X-ray structures are determined from cryocooled crystals, but it is unclear whether cryocooling distorts functionally relevant flexibility. Here we compare independently acquired pairs of high-resolution data sets of a model Michaelis complex of dihydrofolate reductase (DHFR), collected by separate groups at both room and cryogenic temperatures. These data sets allow us to i...

Cryptosporidiosis is an emerging infectious disease that can be life-threatening in an immune-compromised individual and causes gastrointestinal distress lasting up to 2 weeks in an immune-competent individual. There are few therapeutics available for effectively treating this disease. We have been exploring dihydrofolate reductase (DHFR) as a potential target in Cryptosporidium. On the basis o...

Neural networks and inductive logic programming (ILP) have been compared to linear regression for modelling the QSAR of the inhibition of E. coli dihydrofolate reductase (DHFR) by 2,4-diamino-5-(substituted benzyl)pyrimidines, and, in the subsequent paper [Hirst, J.D., King, R.D. and Sternberg, M.J.E. J. Comput.-Aided Mol. Design, 8 (1994) 421], the inhibition of rodent DHFR by 2,4-diamino-6,6-...

BACKGROUND Recurrent head and neck squamous cell carcinoma (HNSCC) remains a difficult cancer to treat. Here, we describe a patient with HNSCC who had complete response to methotrexate (MTX) after progressing on multiple cytotoxic agents, cetuximab, and AMG-479 (monoclonal antibody against insulin-like growth factor-1 receptor [IGF-1R]). METHODS The clinical information was collected by a ret...

Numerous new antifolate drugs have been developed in an attempt to overcome the potential mechanisms of tumor cell resistance to methotrexate, which can include decreased drug transport into cells; decreased polyglutamation, leading to increased drug efflux from cells; decreased drug affinity for folate-dependent enzymes; mutations of dihydrofolate reductase (DHFR), a key enzyme required for th...

We describe the construction and analysis of recombinant DNA libraries representative of chromosomes 1 and 2 of Chinese hamster (Cricetulus griseus). Propidium-iodide stained chromosomes were purified by flow cytometric analysis and sorting, and EcoRI digests of purified DNA were cloned into the bacteriophage vector Charon 4A. These libraries contain DNA complementary to 63% and 69% of nick-tra...

Much work has gone into understanding the physical basis of the enormous catalytic power of enzymes over the last 50 years or so. Nevertheless, the detailed mechanism used by Nature's catalysts to speed chemical transformations remains elusive. DHFR (dihydrofolate reductase) has served as a paradigm to study the relationship between the structure, function and dynamics of enzymatic transformati...

Plasmodium falciparum present in blood samples collected before and 3 weeks after treatment with either pyrimethamine-sulfadoxine or chlorproguanil-dapsone was analyzed for variants of the genes coding for the target enzymes of antifolate drugs, dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS). Fragments of the genes were amplified by polymerase chain reactions, and variants...