Figure 2.

UV-crosslinking analysis of ssDNA:O·P·DnaB nucleoprotein complexes. Radiolabeled RM55 oligonucleotide was incubated in the presence of AMP-PNP, λ O (O), λ P (P), and/or E. coli DnaB (B) proteins as indicated. Assembled nucleoprotein complexes were mixed with unlabeled competitor, irradiated with UV light, and resolved by electrophoresis through an SDS/10% polyacrylamide gel. The migration positions of covalent protein-DNA complexes containing 1 molecule of ssDNA and 1 monomer of either O (λ O¹), P (λ P¹), or DnaB (DnaB¹) proteins are indicated. M, ¹⁴C-labeled protein molecular weight standards (× 10⁻³).