TY  - JOUR
A1  - Tessmer, Ingrid
A1  - Melikishvili, Manana
A1  - Fried, Michael G.
T1  - Cooperative cluster formation, DNA bending and base-flipping by O\(^6\)-alkylguanine-DNA alkyltransferase
JF  - Nucleic Acids Research
N2  - O\(^6\)-Alkylguanine-DNA alkyltransferase (AGT) repairs mutagenic O\(^6\)-alkylguanine and O\(^4\)-alkylthymine adducts in DNA, protecting the genome and also contributing to the resistance of tumors to chemotherapeutic alkylating agents. AGT binds DNA cooperatively, and cooperative interactions are likely to be important in lesion search and repair. We examined morphologies of complexes on long, unmodified DNAs, using analytical ultracentrifugation and atomic force microscopy. AGT formed clusters of 11 proteins. Longer clusters, predicted by the McGhee-von Hippel model, were not seen even at high [protein]. Interestingly, torsional stress due to DNA unwinding has the potential to limit cluster size to the observed range. DNA at cluster sites showed bend angles (similar to 0, similar to 30 and similar to 60 degrees) that are consistent with models in which each protein induces a bend of similar to 30 degrees. Distributions of complexes along the DNA are incompatible with sequence specificity but suggest modest preference for DNA ends. These properties tell us about environments in which AGT may function. Small cooperative clusters and the ability to accommodate a range of DNA bends allow function where DNA topology is constrained, such as near DNA-replication complexes. The low sequence specificity allows efficient and unbiased lesion search across the entire genome.
KW  - inactivation
KW  - nucleotide excision-repair
KW  - atomic-force microscopy
KW  - noncooperative binding
KW  - restricition enzymes
KW  - complex stability
KW  - stranded DNAs
KW  - protein
KW  - chemotherapy
KW  - AGT
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133949
VL  - 40
IS  - 17
ER  - 
TY  - JOUR
A1  - Espina, Laura
A1  - Pagán, Rafael
A1  - López, Daniel
A1  - García-Gonzalo, Diego
T1  - Individual Constituents from Essential Oils Inhibit Biofilm Mass Production by Multi-Drug Resistant Staphylococcus aureus
JF  - Molecules
N2  - Biofilm formation by Staphylococcus aureus represents a problem in both the medical field and the food industry, because the biofilm structure provides protection to embedded cells and it strongly attaches to surfaces. This circumstance is leading to many research programs seeking new alternatives to control biofilm formation by this pathogen. In this study we show that a potent inhibition of biofilm mass production can be achieved in community-associated methicillin-resistant S. aureus (CA-MRSA) and methicillin-sensitive strains using plant compounds, such as individual constituents (ICs) of essential oils (carvacrol, citral, and (+)-limonene). The Crystal Violet staining technique was used to evaluate biofilm mass formation during 40 h of incubation. Carvacrol is the most effective IC, abrogating biofilm formation in all strains tested, while CA-MRSA was the most sensitive phenotype to any of the ICs tested. Inhibition of planktonic cells by ICs during initial growth stages could partially explain the inhibition of biofilm formation. Overall, our results show the potential of EOs to prevent biofilm formation, especially in strains that exhibit resistance to other antimicrobials. As these compounds are food additives generally recognized as safe, their anti-biofilm properties may lead to important new applications, such as sanitizers, in the food industry or in clinical settings.
KW  - Listeria monocytogenes
KW  - carvacrol
KW  - strains
KW  - essential oils
KW  - anti-biofilm
KW  - bacterial biofilms
KW  - food industry
KW  - antibacterial
KW  - inactivation
KW  - components
KW  - citrus
KW  - biofilms
KW  - Staphylococcus aureus
KW  - (+)-limonene
KW  - citral
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151845
VL  - 20
SP  - 11357
EP  - 11372
ER  -