Biology Reference
In-Depth Information
Abstract
Sensor proteins play crucial roles in maintaining homeostasis of cells by sensing
changes in extra- and intracellular chemical and physical conditions to trigger bio-
logical responses. It has recently become clear that gas molecules function as sig-
nalling molecules in these biological regulatory systems responsible for
transcription, chemotaxis, synthesis/hydrolysis of nucleotide second messengers,
and other complex physiological processes. Haem-containing sensor proteins are
widely used to sense gas molecules because haem can bind gas molecules revers-
ibly. Ligand binding to the haem in the sensor proteins triggers conformational
changes around the haem, which results in their functional regulation. Spectroscopic
and crystallographic studies are essential to understand how these sensor proteins
function in these biological regulatory systems. In this chapter, I discuss structural
and functional relationships of haem-containing PAS and PAS-related families of
the sensor proteins.
ABBREVIATIONS
Ax
PDEA1
Acetobacter xylinum
phosphodiesterase A1
Bj
FixL FixL protein from
Bradyrhizobium japonicum
Bj
FixLH haem-containing PAS domain of
Bj
FixL
BMAL1 brain and muscle Arnt-like protein
CooA transcriptional regulator for the CO oxidation operon
CRP cyclic AMP receptor protein
Cyclic di-GMP bis-(3
0
,5
0
)-cyclic dimeric guanosine monophosphate
DGC diguanylate cyclase
EAL phosphodiesterase having an amino acid sequence motif of
Glu-Ala-Leu
Ec
Dos direct oxygen sensor from
Escherichia coli
EPR electron paramagnetic resonance
EXAFS extended X-ray absorption fine structure
FNR regulatory factor for fumarate and nitrate reduction
GAF acronyms of cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA
H-NOX haem-nitric oxide/oxygen binding
NPAS2 neuronal PAS domain protein 2
PAS acronyms of Period, Arnt, and Sim
PDE phosphodiesterase
RcoM regulator of CO metabolism
sh shoulder peak
Sm
FixL FixL protein from
Sinorhizobium meliloti
Sm
FixLH haem-containing PAS domain of
Sm
FixL
Sw
Mb sperm whale myoglobin
UV-vis
ultraviolet/visible
