Fig 7.

Cross-linking results in a shift in sedimentation coefficient value and collapse of the protein complex into a globular form. (A) Protein sedimentation profile for (His₁₀)Mus81-(GST)Mms4 in the presence and absence of formaldehyde cross-linker. (B) Table summary of sedimentation coefficient values (S-value) for both untagged (His₁₀)Mus81-Mms4 and (His₁₀)Mus81-(GST)Mms4-purified protein. Calculated M_rs are given as determined by the globular standard (indicated gMr), as are the predicted M_rs for the single heterodimer and dimer of heterodimers. (C) Eight randomly selected (His₁₀)Mus81-(GST)Mms4 protein particles acquired with negative-stain transmission electron microscopy are shown along with their associated class averages. Bar, 10 nm. (D) Relative contribution of elongated particle classes between (His₁₀)Mus81-Mms4 and (His₁₀)Mus81-(GST)Mms4 to the total number of particles. Elongated particles were defined as having a calculated ratio greater than 1.5 when comparing measurements of the longest particle diameter against the corresponding perpendicular diameter.