منابع مشابه
Site-specific mutagenesis of histidine residues in the lac permease of Escherichia coli.
The lacY gene of Escherichia coli, which encodes the lac permease, has been modified by oligonucleotide-directed, site-specific mutagenesis such that each of the four histidine residues in the molecule is replaced with an arginine residue. Replacement of histidine-35 and histidine-39 with arginine has no apparent effect on permease activity. In contrast, replacement of either histidine-205 or h...
متن کاملSite-directed mutagenesis of Pro327 in the lac permease of Escherichia coli.
By use of oligonucleotide-directed, site-specific mutagenesis, Pro327 in the lac permease of Escherichia coli has been replaced with Ala, Gly, or Leu. Permease with Ala at position 327 catalyzes lactose/H+ symport in a manner indistinguishable from wild-type permease. Permease with Gly at position 327, on the other hand, exhibits about one-tenth the activity of wild-type permease but catalyzes ...
متن کاملlac permease of Escherichia coli containing a single histidine residue is fully functional.
Arg-302, His-322, and Glu-325, neighboring residues in putative helices IX and X of the lac permease (lacY gene product) of Escherichia coli, play an important role in lactose/H+ symport, possibly as components of a catalytic triad similar to that postulated for the serine proteases [Kaback, H. R. (1987) Biochemistry 26, 2071-2076]. By using restriction fragments of lacY genes harboring specifi...
متن کاملCharacterization of site-directed mutants in the lac permease of Escherichia coli. 1. Replacement of histidine residues.
Wild-type lac permease from Escherichia coli and two site-directed mutant permeases containing Arg in place of His35 and His39 or His322 were purified and reconstituted into proteoliposomes. H35-39R permease is indistinguishable from wild type with regard to all modes of translocation. In contrast, purified, reconstituted permease with Arg in place of His322 is defective in active transport, ef...
متن کاملImmuno-gold Labelling of Chlamydia trachomatis
Background Chlamydia trachomatis is considered as an important cause of preventable sexually transmitted diseases worldwide. It is known to be of an obligate intracellular nature and enters its target cells via an endocytic process. As major outer membrane protein (MOMP) is one of the main candidates for the attachment and entry of chlamydia to the host cells we have tried to label the epitopes...
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ژورنال
عنوان ژورنال: FEBS Letters
سال: 1972
ISSN: 0014-5793
DOI: 10.1016/0014-5793(72)80401-0