Crystal structure of a biologically functional form of PriB from Escherichia coli reveals a potential single-stranded DNA-binding site.
PriB is not only an essential protein necessary for the replication restart on the collapsed and disintegrated replication fork, but also an important protein for assembling of primosome onto PhiX174 genomic DNA during replication initiation. Here we report a 2.0-A-resolution X-ray structure of a biologically functional form of PriB from Escherichia coli. The crystal structure revealed that despite a low level of primary sequence identity, the PriB monomer, as well as the dimeric form, are structurally identical to the N-terminal DNA-binding domain of the single-stranded DNA-binding protein (SSB) from Escherichia coli, which possesses an oligonucleotides-binding-fold. The oligonucleotide-PriB complex model based on the oligonucleotides-SSB complex structure suggested that PriB had a DNA-binding pocket conserved in SSB from Escherichia coli and might bind to single-stranded DNA in the manner of SSB. Furthermore, surface plasmon resonance analysis and fluorescence measurements demonstrated that PriB binds single-stranded DNA with high affinity, by involving tryptophan residue. The significance of these results with respect to the functional role of PriB in the assembly of primosome is discussed.
Shioi
Seijiro
S
Department of Immunology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Ose
Toyoyuki
T
Maenaka
Katsumi
K
Shiroishi
Mitsunori
M
Abe
Yoshito
Y
Kohda
Daisuke
D
Katayama
Tsutomu
T
Ueda
Tadashi
T
D000595:Amino Acid Sequence; D001665:Binding Sites; D003198:Computer Simulation; D018360:Crystallography, X-Ray / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; C086004:PriB protein, E coli