Figure 1.

Electrospray ionization-mass spectra of different combinations of the clamp-loader subunits from B. subtilis sprayed from 1 M ammonium acetate, pH7.5. The τ subunits are represented by red spheres, while the δ and δ′ subunits are represented by green and blue spheres, respectively. A, τ subunit in isolation; B, equimolar mixture of τ and δ subunits; C, equimolar mixture of τ and δ′ subunits; D, equimolar mixture of τ₃, δ and δ′ subunits, resulting in the formation of the clamp-loader complex. E, The clamp-loader complex analysed under high collisional energy, resulting in a partial dissociation of δ and δ′ subunits (peaks corresponding to the low charged τ₃-δ and τ₃-δ′ after dissociation are magnified in the shaded region of the spectrum).