Mutant lambda repressors with increased operator affinities reveal new, specific protein-DNA contacts

Article Abstract:

Previous investigations have isolated mutant lambda repressors with increased affinity for operator DNA. An investigation was conducted to determine the basis of the increased affinity for the lambda operator in these mutants. The results showed that single up-mutations result in the formation of new salt-bridges or improvement of the ability of repressor monomers to form dimers, although binding specificity is not altered. A double mutant, Lys-4 - Gln/Gly-48 - Ser, resulted in a repressor which bound more poorly than the parental repressors, but could bind other operators better than the parents. Possible explanations for this double up-mutation are discussed.

Analysis, Microbial mutation, Operator regions (Genetics)

---

The effects of central asymmetry on the propagation of palindromic DNA in bacteriophage lambda are consistent with cruciform extrusion in vivo

Article Abstract:

Bacteriophage lambda propagation in strains containing longpalindromic sequences and in those with interrupted palindromic sequences were compared. Phages with uninterrupted palindromic sequence exhibited more injurious phenotypes than did strains containing central asymmetry in the palindromic sequence. The length of asymmetry was also found out to be inversely proportional to phenotype severity implying the dependence of phenotypic expression on the central sequences in the palindromic sequence.

---

Regulation of syrM and nodD3 in Rhizobium melitoti

Article Abstract:

The nod gene operons of Rhizobium and their expression were studied. The relationships between syrM expression and nodD3 expression were investigated using gene fusions. Screening for beta-glucoronidase activity was done using fluorescent assay. Results were different from those obtained by other workers. SyrM effects on nod gene expression were mediated by nodD3 while nodD3 expression was influenced by syrM. There was no evidence for luteolin induction of nodD3.

Rhizobium

Similar abstracts:

• Abstracts: Mutations at the murine motheaten locus are within the hematopoietic cell protein-tyrosine phosphatase (Hcph) gene
• Abstracts: Dynamic expression of cell-surface antigens probed with Candida albicans-specific monoclonal antibodies
• Abstracts: Mutant studies of phosphofructo-2-kinases do not reveal an essential role of fructose-2,6-bisphosphate in the regulation of carbon fluxes in yeast cells
• Abstracts: Activity, expression and function of a second Drosophila protein kinase A catalytic subunit gene. The embryonically active gene, unkempt, of Drosophila encodes a Cys(sub 3)His finger protein
• Abstracts: Habitat selection by the western kingbird in western Nebraska: a hierarchical analysis. part 2 On breeding performance, colony growth and habitat selection in Buff-necked Ibis

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.