Corrin Ring Modifications Reveal the Chemical and Spatial Requirements for the B-btuB Riboswitch Interaction.

The btuB riboswitch is a regulatory RNA sequence controlling gene expression of the outer membrane B transport protein BtuB by specifically binding coenzyme B (AdoCbl) as its natural ligand. The B sensing riboswitch class is known to accept various B derivatives, leading to a division into two riboswitch subclasses, dependent on the size of the apical ligand. Here we focus on the role of side chains b and e on affinity and proper recognition, i.

Characterization of the full-length btuB riboswitch from Klebsiella pneumoniae.

Riboswitches are cis-regulatory RNA elements on the mRNA level that control the expression of the downstream coding region. The interaction of the riboswitch with its specific metabolite, which is related to the function of the controlled gene, induces a structural change of the RNA architecture. Consequently, gene regulation is induced by un/masking of the ribosome binding site (RBS).

Quinoline-2-carboxaldehyde thiosemicarbazones and their Cu(II) and Ni(II) complexes as topoisomerase IIa inhibitors.

A series of quinoline-2-carboxaldehyde thiosemicarbazones and their copper(II) and nickel(II) complexes were synthesized and characterized. In all complexes the ligands are in the E configuration with respect to the imino bond and behave as terdentate. The copper(II) complexes form square planar derivatives with one molecule of terdentate ligand and chloride ion.

[Findings in relation to serum and urinary iron in heterozygotic beta-thalassemia].

Iron status (expressed as serum ferritin and iron levels) has been compared in normal and in heterozygous beta-thalassemic subjects. A higher serum ferritin concentration has been found in beta-thalassemic males, showing, therefore, a shift towards super-normal values of the balance between tissue iron and serum ferritin levels. In beta-thalassemic subjects the serum ferritin levels have been found in the normal range and this seems to be correlated with an adequate and ready iron supply by protein transferrin to hyperplastic bone marrow.