1. Structural and DNA binding properties of mycobacterial integration host factor mIHF
- Author
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Odermatt, Nina, Lelli, Moreno, Herrmann, Torsten, Abriata, Luciano, Japaridze, Aleksandre, Voilquin, Hubert, Singh, Rajkumar, Piton, Jérémie, Emsley, Lyndon, Dietler, Giovanni, Cole, Stewart, Stewart, T, Cole, École, Polytechnique, Fédérale, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
- Subjects
DNA, Bacterial ,Integration Host Factors ,Protein Conformation, alpha-Helical ,Magnetic Resonance Spectroscopy ,Nucleoid Associated Protein ,Globular protein ,[SDV]Life Sciences [q-bio] ,mIHF ,Streptomyces coelicolor ,Microscopy, Atomic Force ,DNA-binding protein ,03 medical and health sciences ,chemistry.chemical_compound ,Structural Biology ,lsr2 ,Nucleoid ,Humans ,Tuberculosis ,DNA binding ,Mycobacterial Integration Host Factor ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Binding Sites ,atomic force microscopy ,biology ,030302 biochemistry & molecular biology ,nucleoid-associated proteins ,dynamics ,Mycobacterium tuberculosis ,NMR structural determination ,biology.organism_classification ,3. Good health ,DNA binding site ,nmr structure determination ,DNA-Binding Proteins ,assignment ,chemistry ,regulator ,bacterial chromatin ,Host-Pathogen Interactions ,Biophysics ,DNA supercoil ,systems ,DNA ,Alpha helix - Abstract
In bacteria, nucleoid associated proteins (NAPs) take part in active chromosome organization by supercoil management, three-dimensional DNA looping and direct transcriptional control. Mycobacterial integration host factor (mIHF, rv1388) is a NAP restricted to Actinobacteria and essential for survival of the human pathogen Mycobacterium tuberculosis. We show in vitro that DNA binding by mIHF strongly stabilizes the protein and increases its melting temperature. The structure obtained by Nuclear Magnetic Resonance (NMR) spectroscopy characterizes mIHF as a globular protein with a protruding alpha helix and a disordered N-terminus, similar to Streptomyces coelicolor IHF (sIHF). NMR revealed no residues of high flexibility, suggesting that mIHF is a rigid protein overall that does not undergo structural rearrangements. We show that mIHF only binds to double stranded DNA in solution, through two DNA binding sites (DBSs) similar to those identified in the x-ray structure of sIHF. According to Atomic Force Microscopy, mIHF is able to introduce left-handed loops of ca. 100 nm size (∼300 bp) in supercoiled cosmids, thereby unwinding and relaxing the DNA.
- Published
- 2020