Studies on the purification and properties of factor Tu from E. coli.
TL;DR: Transfer factor Tu has been purified to apparent homogeneity from extracts of Escherichia coli and contains a sulfhydryl group essential for GDP binding, which in Tu free of nucleotide reacts readily with N-ethylmaleimide, but in Tu-GDP is almost inert.
About: This article is published in Archives of Biochemistry and Biophysics.The article was published on 1970-11-01. It has received 198 citations till now. The article focuses on the topics: Dissociation constant.
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521 citations
TL;DR: Comparison of the structure with that of EF-TuGDP reveals major mutual rearrange-ments of the three domains of the molecule, and molecular mechanisms are proposed for transductlon and amplification of the signal induced by GTP binding.
Abstract: The crystal structure of intact elongation factor Tu (EF-Tu) from Thermus thermophilus has been determined and refined at an effective resolution of 1.7 A, with incorporation of data extending to 1.45 A. The effector region, including interaction sites for the ribosome and for transfer RNA, is well defined. Molecular mechanisms are proposed for transductlon and amplification of the signal induced by GTP binding as well as for the intrinsic and effector-enhanced GTPase activity of EF-Tu. Comparison of the structure with that of EF-Tu–GDP reveals major mutual rearrange-ments of the three domains of the molecule.
506 citations
TL;DR: The crystal structure of the EF- Tu·EF-Ts complex from Escherichia coli has been determined to a resolution of 2.5 Å and the interaction of EF-Ts with EF-Tu results principally in the disruption of the Mg2+ ion binding site, thereby reducing the affinity of EF -Tu for guanine nucleotides.
Abstract: The crystal structure of the EF-Tu·EF-Ts complex from Escherichia coli has been determined to a resolution of 2.5 A. The complex contains two subunits of each of the elongation factors. The two EF-Ts molecules form a tight dirtier, but there is little contact between the two EF-Tu molecules. The interaction of EF-Ts with EF-Tu results principally in the disruption of the Mg2+ ion binding site, thereby reducing the affinity of EF-Tu for guanine nucleotides.
277 citations
TL;DR: The study of kinetics of polyphenylalanine synthesis and dependence of the synthesis rate on the Mg 2+ concentration in the factor-free, EF-T u -dependent and EF-G-dependent translation systems has demonstrated that the elongation factors with GTP promote ribosomal mechanisms of aminoacyl-tRNA binding and translocation, respectively.
236 citations
TL;DR: The polypeptide elongation factors Tu-GDP, Ts and Tu-Ts have been purified from Escherichia coli to homogeneous state as judged by criteria of ultracentrifugation and disc gel electrophoresis.
236 citations
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TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.
289,852 citations
TL;DR: The results show that the polyacrylamide gel electrophoresis method can be used with great confidence to determine the molecular weights of polypeptide chains for a wide variety of proteins.
19,381 citations
TL;DR: The technique of disc electrophoresis has been presented, including a discussion of the technical variables with special reference to the separation of protein fractions of normal human serum.
Abstract: Summary
The technique of disc electrophoresis has been presented, including a discussion of the technical variables with special reference to the separation of protein fractions of normal human serum.
17,771 citations
TL;DR: A modification of the naphthalene-dioxane-PPO liquid scintillator has been described which will allow up to 3.0 ml of an aqueous solution to be counted as mentioned in this paper.
7,634 citations
TL;DR: A procedure is presented which strongly reduces or elimi- nates these interactions, normalizes their absorption, and consequently permits a more precise analysis of tryptophan and tyrosine in proteins.
Abstract: A rapid method for the determination of tryptophan in proteins is presented. It is based on ab- sorbance measurements at 288 and 280 mp of the protein dissolved in 6 M guanidine hydrochloride. Blocked tryptophanyl (N-acetyl-L-tryptophanamide) and tyrosyl (glycyl-L-tyrosylglycine) compounds were selected as C urrent methods of protein amino acid analysis do not give quantitative values for tryptophan and conse- quently the amino acid compositions, which are other- wise complete, fail to report tryptophan values. The principal reason for this situation is that the standard procedure of protein hydrolysis in strong acid results in the destruction of tryptophan (Hill, 1965). Therefore a second procedure is required to measure tryptophan. Alkaline hydrolysis is less destructive but does not give quantitative recoveries generally (Spies and Chambers, 1949). Enzymatic hydrolysis of proteins can give quanti- tative yields of tryptophan but this method may not be generally valid (Hill and Schmidt, 1962). The hydrolytic problem can be circumvented by meas- uring tryptophan in the intact protein. A chemical method has been developed which has not been exploited adequately (Spies and Chambers, 1948, 1949). On the other hand, considerable effort has been expended in developing absorption spectroscopic procedures to measure tryptophan and tyrosine in unhydrolyzed pro- teins. Holiday (1936) and Goodwin and Morton (1946) have measured the absorption of proteins in 0.1 M NaOH and computed their tryptophan and tyrosine contents based on comparison with the absorption of the two amino acids. A modification of these techniques has been presented by Bencze and Schmid (1957). The pre- ceding three methods do not give quantitative results. The behavior of the chromophores has not been nor- malized and the two models, i.e., tryptophan and tyro- sine, are not completely adequate. A procedure is sug- gested in this report which strongly reduces or elimi- nates these interactions, normalizes their absorption, and consequently permits a more precise analysis of tryptophan and tyrosine in proteins.
3,323 citations