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April H. Baugher, Jon M. Goetz, Lynda M. McDowell, Haiyong Huang, Karen L. Wooley and Jacob Schaefer
AbstractRotational-echo double-resonance (REDOR) C NMR spectra (with F dephasing) have been obtained of 6-fluorotryptophan complexed by a polymeric amphiphilic nanosphere consisting of a polystyrene core covalently attached to a poly(acrylic acid)-polyacrylamide shell. The REDOR spectra show that aromatic carbons from the polystyrene core and oxygenated carbons in the poly(acrylic acid)-polyacrylamide shell are both proximate to the F of 6-fluorotryptophan. Molecular modeling restrained by distances inferred from the REDOR spectra suggests that all of the 6-fluorotryptophans are in the shell but within 10Å of the core-shell interface.
Abstract | Full Text | PDF (142 kb) - Effects of fluorine substitution on the structure and dynami...Effects of fluorine substitution on the structure and dynamics of complexes of dihydrofolate reductase (Escherichia coli)
Biophysical Journal, Volume 73, Issue 3, 1 September 1997, Pages 1579-1592
E.Y. Lau and J.T. Gerig
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Abstract | PDF (1500 kb) - Molecular and Biochemical Studies of Chondramide Formation—H...Molecular and Biochemical Studies of Chondramide Formation—Highly Cytotoxic Natural Products from Chondromyces crocatus Cm c5
Chemistry & Biology, Volume 13, Issue 6, 1 June 2006, Pages 667-681
Shwan Rachid, Daniel Krug, Brigitte Kunze, Irene Kochems, Maren Scharfe, T. Mark Zabriskie, Helmut Blöcker and Rolf Müller
SummaryThe jaspamide/chondramide family of depsipeptides are mixed PKS/NRPS natural products isolated from marine sponges and a terrestrial myxobacterium that potently affect the function of the actin cytoskeleton. As a first step to improve production in heterologous host cells and permit genetic approaches to novel analogs, we have cloned and characterized the chondramide biosynthetic genes from the myxobacterium Cm c5. In addition to the expected PKS and NRPS genes, the cluster encodes a rare tyrosine aminomutase for β-tyrosine formation and a previously unknown tryptophan-2-halogenase. Conditions for gene transfer into Cm c5 were developed, and inactivation of several genes corroborated their proposed function and served to define the boundaries of the cluster. Biochemical characterization of the final NRPS adenylation domain confirmed the direct activation of β-tyrosine, and fluorinated chondramides were produced through precursor-directed biosynthesis.
Summary | Full Text | PDF (687 kb) - …more
Copyright © 1997 The Biophysical Society. All rights reserved.
Biophysical Journal, Volume 72, Issue 1, 490-498, 1 January 1997
doi:10.1016/S0006-3495(97)78690-9
Research Article
19F NMR measurements of the rotational mobility of proteins in vivo
S.P. Williams, P.M. Haggie and K.M. Brindle
Department of Biochemistry, University of Cambridge, United Kingdom.
Abstract
Three glycolytic enzymes, hexokinase, phosphoglycerate kinase, and pyruvate kinase, were fluorine labeled in the yeast Saccharomyces cerevisiae by biosynthetic incorporation of 5-fluorotryptophan. 19F NMR longitudinal relaxation time measurements on the labeled enzymes were used to assess their rotational mobility in the intact cell. Comparison with the results obtained from relaxation time measurements of the purified enzymes in vitro and from theoretical calculations showed that two of the labeled enzymes, phosphoglycerate kinase and hexokinase, were tumbling in a cytoplasm that had a viscosity approximately twice that of water. There were no detectable signals from pyruvate kinase in vivo, although it could be detected in diluted cell extracts, indicating that there was some degree of motional restriction of the enzyme in the intact cell.
