Biology Reference
In-Depth Information
CHAPTER FOUR
Functional Genomics
of Metalloregulators in
Cyanobacteria
L. Botello-Morte, A. González, M. T. Bes, M. L. Peleato, M. F. Fillat
1
Department of Biochemistry and Molecular and Cell Biology, Faculty of Sciences, Institute for Biocomputation
and Physics of Complex Systems (BIFI), University of Zaragoza, Pedro Cerbuna, Spain
1
Corresponding author: E-mail:fillat@unizar.es
Contents
1. Introduction
108
2. General Features of Metalloregulators
109
3. Main Families of Metalloregulators in Cyanobacteria
109
3.1. The Fur Superfamily
109
3.1.1. Structural features of Fur proteins
110
3.1.2. Occurrence and functions of Fur paralogues in cyanobacteria
113
3.1.3. Deciphering the FurA regulon
121
3.1.4. Genetic regulation of cyanobacterial Fur proteins
124
3.1.5. Metabolic and regulatory networks involving Fur proteins
128
3.2. Regulation of Iron-Sulphur Cluster Assembly
131
3.2.1. The iron sulphurcluster (isc) system
132
3.2.2. The sulphur utilization factor (suf ) system
132
3.3. Manganese Homeostasis in Cyanobacteria: the ManR and RfrA Regulators
133
3.4. The ArsR/SmtB Family of Metal-Sensor Proteins
136
3.4.1. Metal-binding sites of SmtB/ArsR family members
137
3.4.2. DNA-binding sites
141
3.4.3. Functions of SmtB proteins
142
3.4.4. Allosteric regulation and autoregulation
144
3.5. The MerR Family of Proteins
144
3.6. The Nickel-Sensor Proteins
146
3.6.1. Nickel-sensing systems in cyanobacteria
146
3.7. Metal Sensors and Nitrogen Metabolism
148
4. Conclusions and Perspectives
148
Abstract
Cyanobacterial metabolism relies on the activity of many enzymes and other proteins
containing metal-rich cofactors that are absent in nonphotosynthetic organisms. Most
of those micronutrients play key roles in or are associated to photosystems, respiratory
electron transport chains and many enzymes involved in nitrogen metabolism. Since
