Stopped-flow NMR spectroscopy: real-time unfolding studies of 6-19F-tryptophan-labeled Escherichia coli dihydrofolate reductase.

Escherichia coli dihydrofolate reductase (DHFR; EC 1.5.1.3) contains five tryptophan residues that have been replaced with 6-19F-tryptophan. The 19F NMR assignments are known in the native, unliganded form and the unfolded form. We have used these assignments with stopped-flow 19F NMR spectroscopy to investigate the behavior of specific regions of the protein in real time during urea-induced unfolding. The NMR data show that within 1.5 sec most of the intensities of the native 19F resonances of the protein are lost but only a fraction (approximately 20%) of the intensities of the unfolded resonances appears. We postulate that the early disappearance of the native resonances indicates that most of the protein rapidly forms an intermediate in which the side chains have considerable mobility. Stopped-flow far-UV circular dichroism measurements indicate that this intermediate retains native-like secondary structure. Eighty percent of the intensities of the NMR resonances assigned to the individual tryptophans in the unfolded state appear with similar rate constants (k approximately 0.14 sec-1), consistent with the major phase of unfolding observed by stopped-flow circular dichroism (representing 80% of total amplitude). These data imply that after formation of the intermediate, which appears to represent an expanded structural form, all regions of the protein unfold at the same rate. Stopped-flow measurements of the fluorescence and circular dichroism changes associated with the urea-induced unfolding show a fast phase (half-time of about 1 sec) representing 20% of the total amplitude in addition to the slow phase mentioned above. The NMR data show that approximately 20% of the total intensity for each of the unfolded tryptophan resonances is present at 1.5 sec, indicating that these two phases may represent the complete unfolding of the two different populations of the native protein.

Official report of proceedings /

Mode of access: Internet.

Followup meeting, held at Houston, Texas, Dec. 5, 1972; transcript of proceedings.

Mode of access: Internet.

Proceedings, Second International Conference on Fixed-Film Biological Processes, July 10-12, 1984, Arlington, Virginia /

"EPA/600/9-85/024a."

Executive session for the third session: transcript of proceedings.

Mode of access: Internet.

Proceedings : first International Conference on Numerical Ship Hydrodynamics, 20-22 Oct. 1975 /

"Dedicated to the memory of Reinier Timman (1917-1975)."

The Baptist World Congress : authorised record of proceedings.

Imprint varies according to location of conference.

Proceedings - Standards Laboratory Conference

Mode of access: Internet.

Rabbinical literature: or, The traditions of the Jews, contained in their Talmud and other mystical writings. Likewise the opinions of that people concerning Messiah, and the time and manner of his appearing; with an appendix comprizing Buxtorf's account of the religious customs and ceremonies of that nation; also, A preliminary enquiry into the origin, progress, authority, and usefulness of these traditions; wherein the sense of the strange allegories in the Talmud and Jewish authors is explained.

The first edition of the German original was issued Frankfurt, 1700, under the title "Entdecktes judenthum", but was suppressed until after a second edition appeared at Königsberg, 1711. Editions of the translation, with preface by J.P. Stehelin, were issued 1732-34 and 1742 under title: The traditions of the Jews ...

The borough of Stoke-upon-Trent, in the commencement of the reign of ... Queen Victoria, comprising its history, statistics, civil polity, & traffic ... also, the manorial history of Newcastle-under-Lyme, and incidental notices of other neighbouring place & objects;

Publication begun in numbers, 8 of which were issued by the author in collaboration with Simeon Shaw. The latter then retired (having contributed nothing after chapter X) and Ward completed the work as sole author.

Journal of proceedings and addresses of the ... annual conferences /

Vols. for 3rd- published under title: Journal of proceedings and addresses of the ... annual conference.

Report of proceedings

At head of title: Workers education in the United States

History, essays, orations and other documents of the sixth general conference of the Evangelical Alliance, held in New York, October 2-12, 1873 /

Binders title: Evangelical alliance. Proceedings, essays, and addresses, 1873.

Journal of proceedings and addresses of the annual meeting

Title varies slightly

Development time and survival of Verrallina funerea (Theobald) (Diptera : Culicidae) immatures and other brackish water mosquito species in southeast Queensland, Australia

Verrallina funerea (Theobald) is a brackish water mosquito that is recognised as an important pest and vector in southeast Queensland, Australia. Immature development time and survival of Ve. funerea was defined in the laboratory in response to a range of temperatures (17-34 degrees C) and salinities (0-35 parts per thousand (p.p.t)). The expression of autogeny in this species was also assessed. Salinity only had a slight effect on mean development time from hatching to adult emergence (7.0-7.4 d at salinities of 0, 17.5 and 31.5 p.p.t) and survival was uniformly high (97.5-99.0%). Mean development times were shorter at 26, 29 and 32 degrees C (7.0, 6.8 and 6.8 d, respectively) and longest at 17 degrees C (12.2 d). The threshold temperature (t) was 5.8 degrees C and the thermal constant (K) was 142.9 degree-days above t. Survival to adulthood decreased from > 95% (at 17-29 degrees C) to 78% (at 32 degrees C) and 0% (at 34 degrees C). No expression of autogeny was observed. Immature development times of Ve. funerea, Ochlerotatus vigilax (Skuse) and Oc. procax (Skuse) were then determined under field conditions at Maroochy Shire. Following tide and rain inundation, cohorts of newly hatched larvae were monitored daily by dipping, and time until pupation was noted. Tidal inundation triggered hatching of Ve. funerea and Oc. vigilax larvae whereas Oc. procax larvae were found only after rain inundation. Estimates of Ve. funerea and Oc. vigilax field development times were similar (8-9 d) while Oc. procax development time was slightly longer (9-10 d). Based on these survey results, control activities targeting Ve. funerea must be initiated 4 d (if using Bacillus thuringiensis var. israelensis de Barjac) or 5 d (if using s-methoprene) after inundation. However, Casuarina glauca Sieber canopy and branchlets covering breeding habitats may present a problem for the penetration of such treatments.