Genetic studies

Genetic studies agree with the structural model... 

The elegant genetic studies by the group of Charles Yanofsky at Stanford University, conducted before the crystal structure was known, confirm this mechanism. The side chain of Ala 77, which is in the loop region of the helix-turn-helix motif, faces the cavity where tryptophan binds. When this side chain is replaced by the bulkier side chain of Val, the mutant repressor does not require tryptophan to be able to bind specifically to the operator DNA. The presence of a bulkier valine side chain at position 77 maintains the heads in an active conformation even in the absence of bound tryptophan. The crystal structure of this mutant repressor, in the absence of tryptophan, is basically the same as that of the wild-type repressor with tryptophan. This is an excellent example of how ligand-induced conformational changes can be mimicked by amino acid substitutions in the protein. 

Hall, J.L., Ramanis, Z., Luck, D.J.L. (1989). Basal body/centriolar DNA Molecular genetic studies in Chlamydomonas. Cell 59, 121-132. 

In turn, an important factor that can damage DNA in nature or at performing molecular genetic studies, is ultraviolet (UV) radiation that is absorbed by this biopolymer at bandwidth maxmum 254 nm. This led to the formation of different DNA photodamages, with increasing of the dose of UV radiation progressed from pyrimidine dimers to single-and double-stranded breaks [Cariello et al., 1988 Lyamichev et al., 1990]. 

E. and Vlek-Noot, C. "The Use of Quantitative Cytochemlcal Analysis In Rapid Prenatal Detection and Somatic Cell Genetic Studies of Metabolic Diseases". Hlstochem. J.,... 

Henry S.A. (1982) Membrane lipids of yeast biochemical mid genetic studies. In The Molecular Biology of the Yeast Saccharomyces, vol. 2. Metabolism and Biosynthesis (eds J.N. Strathem, E.W. Jones J.R. Broach), pp. 101-158. Cold Spring Harbor, NY Cold Spring Harbor Laboratory. 

We describe here the molecular identification of the pelZ gene and the genetic studies of the regulations affecting its expression. Following overproduction of the PelZ protein, biochemical studies were undertaken in order to define some enzymatic characteristics of PelZ activity. 

R. A. Jeffer.son, Beta-glucuronidase (GUS) transposons for ecological and genetic studies of rhizobia and other gram-negative bacteria. Microbiology 14l 69l (1995). 

Family history of RA. Genetic studies demonstrate a strong correlation between RA and the presence of major histocompatibility complex class II human leukocyte antigens (HLA), specifically HLA-DR1 and HLA-DR4.4,5 HLA is a molecule associated with the presentation of antigens to T lymphocytes. 

---