Biology Reference
In-Depth Information
CHAPTER ONE
Haem-Based Sensors: A Still
Growing Old Superfamily
Francesca Germani, Luc Moens, Sylvia Dewilde
1
Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
1
Corresponding author: e-mail address: sylvia.dewilde@ua.ac.be
Contents
1.
Introduction and Background: Why Haem-Based Sensors?
2
2. Functions of the Haem-Based Sensors
3
2.1 Haem-based sensors with aerotactic function
4
2.2 Haem-based sensors with gene-regulating function
7
2.3 Haem-based sensors with enzymatic function
24
2.4 Haem-based sensors with unknown function
24
2.5 Non-haem globin sensors
26
3. The Evolution of the Globins
28
4. Conclusions and Future Perspectives
29
Acknowledgement
30
References
30
Abstract
The haem-based sensors are chimeric multi-domain proteins responsible for the cellular
adaptive responses to environmental changes. The signal transduction is mediated by
the sensing capability of the haem-binding domain, which transmits a usable signal to
the cognate transmitter domain, responsible for providing the adequate answer.
Four major families of haem-based sensors can be recognized, depending on the
nature of the haem-binding domain: (i) the haem-binding PAS domain, (ii) the
CO-sensitive carbon monoxide oxidation activator, (iii) the haem NO-binding domain,
and (iv) the globin-coupled sensors. The functional classification of the haem-binding
sensors is based on the activity of the transmitter domain and, traditionally, comprises:
(i) sensors with aerotactic function; (ii) sensors with gene-regulating function; and
(iii) sensors with unknown function. We have implemented this classification with newly
identified proteins, that is, the Streptomyces avermitilis and Frankia sp. that present a
C-terminal-truncated globin fused to an N-terminal cofactor-free monooxygenase,
the structural-related class of non-haem globins in Bacillus subtilis, Moorella thermo-
acetica, and Bacillus anthracis, and a haemerythrin-coupled diguanylate cyclase in Vibrio
cholerae.
This review summarizes the structures, the functions, and the structure
-
function
relationships known to date on this broad protein family. We also propose unresolved
questions and new possible research approaches.