Structural and functional characterization of bacterial LOV domain containing blue-light photoreceptors [Elektronische Ressource] / Cao, Zhen

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• Biologie

Informations

• Publié par: heinrich-heine-universitat_dusseldorf
• Publié le: 01 janvier 2010
• Nombre de lectures: 60
• Langue: Deutsch
• Poids de l'ouvrage: 4 Mo

Extrait

Structural and Functional
Characterization of Bacterial LOV
Domain-containing Blue-Light
Photoreceptors





Cao, Zhen
aus Shandong, V.R. China



Dissertation
Zur
Erlangung des akademischen Grades eines Doktors der
Mathematisch-Naturwissenschaftlichen Fakultät
der Heinrich-Heine Universität Düsseldorf






Mülheim an der Ruhr, April 2010





































Referent: Prof. Dr. W. Gärtner
Koreferent: Prof. Dr. K.-E. Jäger
Zusammenfassung

Ende des 19. Jahrhunderts berichteten Charles Darwin und sein Sohn über ein
interessantes Phänomen, das in verschiedenen Pflanzenarten beobachtet
worden war: „Phototropismus“, ein lichtabhängiges Richtungswachstum in
Richtung der Lichtquelle. Allerdings wurde das zugehörige Photorezeptorprotein,
Phototropin, mit einer hochkonservierten LOV- (light, oxygen, voltage) Domäne
erst gegen Ende des 20. Jahrhunderts identifiziert. In Folge konnte
nachgewiesen werden, dass die Existenz dieses konservierten Signal-gebenden
Moduls nicht auf Pflanzen beschränkt war, sondern im Gegenteil weit verbreitet
in allen drei Reichen des Lebens mit Ausnahme der Tiere vorhanden ist.

YtvA aus Bacillus subtilis, ein Protein mit 261 Aminosäuren, war das erste
bakterielle LOV-Domänen enthaltende Protein, für das nachgewiesen wurde,
dass es einen Phototropin vergleichbaren Photozyklus durchläuft. Seither wächst
die Kenntnis über prokaryotische LOV-Domänen Proteine extrem, und viele
andere bakterielle LOV-Proteine mit erstaunlich unterschiedlichen
Effektordomänen wurden charakterisiert.

Mit der vorgelegten Dissertation soll unsere Kenntnis über die molekularen
Grundlagen der Signaltransduktion innerhalb verschiedener LOV-Domänen
Proteine erweitert werden. Das Erstellen einer Verbindung zwischen der Struktur
dieser Proteine und ihrer (physiologischen) Funktion ist ebenfalls Teil dieser
Arbeit.

Die funktionelle Charakterisierung von YtvA aus B. subtilis wird hier fortgesetzt
unter Einbeziehung der kürzlich entdeckten NTP-Bindungsfunktion, der
Interdomänen-Interaktion und des Kommunikations-„Weges“, der ausführlich
untersucht wurde. Die dreidimensionale Struktur einer weiteren LOV-Domäne
1aus B. amyloliquefaciens ergab weitere Informationen über die Dimerisierung
von LOV-Domänen und zeigte einen neuen Typus einer Dimerenanordnung.

Weitere bakterielle LOV-enthaltende Proteine mit unterschiedlichen
Effektordomänen wurden hier zum ersten Mal charakterisiert. Hierzu gehört ein
Blaulicht-reguliertes Zweikomponenten-Protein aus Pseudomonas syringae und
ein LOV-Domänen enthaltendes GGDEF/EAL-Protein aus Synechococcus. In
beiden Proteinen sind Blaulicht-sensitive LOV-Domänen mit gut charakterisierten
Signal-gebenden Modulen verknüpft, die in vielen bakteriellen Spezies weit
verbreitet sind.















2Summary



thIn the late 19 century, Charles Darwin and his son had noticed in several plant
species an interesting feature: phototropism, a light dependent directional growth
towards the light source. However, the responsible photoreceptor protein,
phototropin with a conserved light, oxygen and voltage (LOV) domain, could only
th
be identified until the end of 20 century. Later, it has been discovered that this
conserved LOV signaling module is not restricted to plants; it is actually widely
distributed in all three kingdoms of life with the only exception of animals.

YtvA from Bacillus subtilis was the first bacterial LOV-domain containing protein
that has been proven to undergo a phototropin-like blue light induced photocycle.
Since then, the knowledge about prokaryotic LOV domain-containing proteins
was rapidly growing and many other bacterial LOV proteins with quite diversified
downstream effector domains have been characterized.

This present thesis broadens significantly our knowledge about the molecular
basis of signal transmission within several bacterial LOV domain-containing
proteins. The connections between the structure of these proteins and their
functions will also be part of this work.

The study of YtvA from Bacillus subtilis has been continued in this present work.
Besides its recently discovered NTP-binding function, the inter-domain
interaction of YtvA and the detailed communicating pathway have been
extensively investigated. A possible common connecting interface for the signal
transmission in this protein was examined. The structure of another LOV domain
from Bacillus amyloliquefaciens that has been solved during this thesis, also
adds further information on LOV domain dimerization and presents a novel type
of dimer formation.
3Some other bacterial LOV-containing proteins with different effector domains
have been characterized for the first time, including a blue light regulated two-
component signaling protein from Pseudomonas syringae and a LOV-containing
GGDEF/EAL protein from Synechococcus. Both these two proteins have
combined the blue light sensing LOV domain to some well-established signaling
modules that are found widely distributed in many bacterial species.

























4Publications and Poster Presentation

Buttani V, Losi A, Eggert T, Krauss U, Jaeger KE, Cao Z., Gärtner W.
Conformational analysis of the blue-light sensing protein YtvA reveals a competitive interface for
LOV-LOV dimerization and interdomain interactions.
Photochem Photobiol Sci. 6:41-9 (2007).

Cao Z., Krauss U, Buttani V, Jaeger KE, Eggert T, Losi A, Gärtner W.
Blue light inducible functions of bacterial LOV proteins.
The 12th European Society for Photobiology Congress,
University of Bath, UK, September 1-6, (2007).

Cao Z., Buttani V, Losi A, Gärtner W.
A blue light inducible two-component signal transduction system in the plant pathogen
Pseudomonas syringae pv. tomato.
Biophys J. 94:897-905 (2008).

Ogata H., Cao Z., Losi A. Gärtner W.
Crystallization and X-ray analysis of LOV domain of blue-light receptor YtvA from Bacillus
amyloliquefaciens FZB42
Acta Crystallogr Sect F Struct Biol Cryst Commun. 65:853-5 (2009).

Tang, Y, Cao Z., Livoti, E, Krauss U, Gärtner W, Losi A.
Mapping the pathway of signal transmission within a blue-light photoreceptor.
Photochem Photobiol Sci. 9:47-56 (2010).

Cao Z., Livoti, E, Losi A, Gärtner W.
A blue-light inducible cyclic diguanylate phosphodiesterase in cyanobacteria.
Photochem Photobiol. 86:606-11(2010).


























5Acknowledgements

Writing this thesis would not have been possible without the help of a number of
people.

First of all, my sincere thanks go to Prof. Dr. Wolfgang Gärtner and Dr. Aba Losi,
my thesis supervisors, who initiated this exciting research project and supported
me by providing fantastic working conditions and excellent scientific guidance.
Prof. Wolfgang Gärtner also gave me great help in revising and organizing this
thesis.

I also would like to thank Prof. Dr. Karl-Erich Jäger, the co-evaluator of this thesis.

Special thanks go to Dr. Ulrich Krauss for helping me a lot throughout my Ph.D.
research. I am also grateful to all the colleagues in my group for many, many
essential discussions and good advices, Dr. Amrit Kaur, Björn Zorn, Gopal
Pathak, Rashmi Shah, Shivani Sharda, and Yifen Tang. I also appreciate Mrs.
Helene Steffen for her great help during the past few years in laboratory.

Very special thanks go to my parents, Xue-jian Cao and Li-juan Yang who fully
supported me throughout my long studies.

Last but not least, I would like to share this work with my wife, Qunzi Zhang.






















6Abbreviation List

Some unusual abbreviations have been repeatedly used in this thesis, below is a
summarized list of all these abbreviations.

aa Amino acid
Asphot Avena sativa phototropin
ATP Adenosine 5’-triphosphate
Atphot Arabidopsis thaliana phototropin
BLUF Blue-Light sensors Using FAD domain