BIAŁKA REGULATOROWE W KONTROLI EKSPRESJI
GENÓW DEGRADACJI ZWIĄZKÓW O STRUKTURZE
AROMATYCZNEJ U BAKTERII RODZAJU PSEUDOMONAS
Katarzyna Hupert-Kocurek, Agnieszka Mrozik, Sylwia Łabużek
Katedra Biochemii Uniwersytetu Śląskiego, ul. Jagiellońska28, 40-032 Katowice, e-mail:
khupert@us.edu.pl
Wpłynęło w styczniu 2006
1. Wstęp. 2. Ogólna budowa i klasyfikacja białek regulatorowych. 3. Rodzina białek regulatorowych LysR 4. Rodzina białek regulatorowych
IclR. 5. Rodzina białek regulatorowych AraC/XylS. 6. Rodzina białek regulatorowych GntR. 7. Regulatory typu TetR i MarR. 8. Rodzina białek regulatorowych XylR/DmpR 9. Dwuskładnikowy system regulacji ekspresji genów katabolicznych. 10. Podsumowanie
Regulatory proteins in control of aromatic compounds degradation
in Pseudomonas
Abstract: A number of degradative pathways of aromatic compounds, such as phenol, toluene xylene and naphthalene, have been found in many strains of genus
Pseudomonas. The expression of these degradative genes is controlled by one or more regulatory proteins. In most cases, the genes coding for the regulator exist near the structural genes, and their protein products activate the transcription in the presence of inducer molecule. Repressor-mediated regulation is rare for genes involved in the catabolism of aromatic
compounds. According to differences in structure, three-demensional conformation and mechanism of regulation, all regulatory proteins are divided into seven families: LysR, IclR, AraC/SylS, GntR families, TetR-, MarR-type
regulators, XylR/DmpR s54-dependent transcriptional regulators and two-component regulatory system.
In general, there are two functional domains in regulatory protein structure. The domain containing the HTH DNA binding motif in regulators from LysR, IclR and GntR family is located at N- terminal end of the polipeptyde. The second one, C-terminal domain is involved in binding of the chemical inducer and oligomerization. Some of regulatory proteins, especially from XylR/DmpR family, posess the third domain, which is responsible for ATP binding and hydrolysis.
Most of identified regulatory proteins which control aromatic degradation pathways bound DNA in specific region called RBS, except LysR type regulators which recognize additional sequence known as ABS. All regulators are synthesized as non-active monomers. In the presence of inducer they oligomerize to dimers, tetramers, hexamers or heptamers depending of
family. As a result of many studies the behavior of different regulatory proteins was discovered. In some cases it has been possible to identify the protein structure, protein-DNA complex formation and conformational changes in regulators after effector binding. In contrast, little is currently known about the interactions between the regulatory protein and effector compounds and how effector binding to the regulatory protein transmits to an activation signal for RNA polymerase. The understanding of these interactions might be an important challenge for the application of bacterial regulatory systems for bioremediation practice, chemical synthesis and as biosensors for measuring the ąuality of soil and
waters.
1. Introduction. 2. Regulatory proteins structure and
elassification. 3. LysR family of regulatory proteins. 4. IclR family of regulatory
proteins. 5. AraC/XylS family of regulatory proteins. 6. GntR family of regulatory
proteins. 7. TetR- and MarR-type protein regulators. 8. XylR/DmpR family of regulatory
proteins. 9. Two-component regulatory system of catabolic genes
expression. 10. Summary
Słowa kluczowe: białka regulatorowe, degradacja, operony, Pseudomonas
Key words: regulatory proteins, degradation, operons, Pseudomonas
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