Biology Reference
In-Depth Information
ABBREVIATIONS
2/2Hb
truncated globin
ApPgb
Pgb from
Aeropyrum pernix
FHb
flavo-haemoglobin
GCS
globin-coupled sensor
Hb
haemoglobin
MaPgb
Pgb from
Methanosarcina acetivorans
MaPgb
*
Methanosarcina acetivorans
protoglobin whose Cys(101)E20 is replaced by Ser;
amino acid residues have been labeled using their three-letter codes the sequence
numbering (in parentheses), and the topological site they occupy within the globin fold
MaPgb
*
-
D
N20 Methanosarcina acetivorans
protoglobin whose the first 20 amino acids at the
N-terminal have been deleted
MaPgb
*
-
D
N20Z Methanosarcina acetivorans
protoglobin whose 33 N-terminal amino acids
have been removed
Mb
myoglobin
MCP
methyl-accepting chemotaxis protein
Pgb
protoglobin
SDgb
single-domain globin
SDSgb
single-domain sensor globin
1. INTRODUCTION
Much of the diversity within the globin superfamily has been disclosed
by progresses achieved in the past 2 decades, which unravelled several novel
haemoglobins (Hbs) endowed with distinct structural and functional fea-
tures. A survey of putative globins in sequenced genomes within all king-
doms of life showed the presence of three globin lineages and two
structural families (
Vinogradov et al., 2006, 2007; Vinogradov, Tinajero-
Trejo, Poole, & Hoogewijs, 2013
). One lineage includes the chimeric
flavo-haemoglobins (FHbs), comprising an N-terminal globin domain
and a C-terminal FAD- and NAD-binding domain, homologous to the
ferredoxin-NADP
reductases and related single-domain globins
(SDgbs); a second lineage includes two-domain globin-coupled sensors
(GCS), single-domain sensor globins (SDSgbs) and a small number of related
single-domain protoglobins (Pgbs) (
Freitas, Hou, & Alam, 2003; Freitas
et al., 2004; Freitas, Saito, Hou, & Alam, 2005; Hou et al., 2001
). All mem-
bers of these two globin families belong to the same structural class
exhibiting the canonical 3/3 globin fold found in myoglobin (Mb), with
the haem group surrounded by the A-, B- and E-helices roughly on one side
and the F-, G- and H-helices on the other (
Bolognesi, Bordo, Rizzi,
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