Fig. 5. Truncated SMC heterodimers are still able to anneal ssDNA. (A) Various terminally truncated Cut3 and Cut14 forms were made. The number indicates the amino acid residue where truncation took place. Truncated forms of Cut3 (or Cut14) were expressed in combination with co-overexpression of the wild-type or truncated forms of Cut14 (or Cut3). (B) One example of the purified truncated complex is shown. Cut14 is bound to the terminally truncated Cut3ΔNC-8Myc lacking both the N- and C-termini. Lanes 1 and 2 in the SDS–polyacrylamide gel stained by CBB represent the wild-type Cut3–Cut14 complex and the truncated complex, respectively. The wild-type Cut3 is highly sensitive to protease during preparation, yielding two bands (Sutani and Yanagida, 1997). (C) DNA reannealing activity remains as strong in Cut3–Cut14ΔNC and Cut3ΔNC–Cut14 as the wild-type combination. In other combinations, the reannealing activity was either null or very weak. (D) Gel shift experiment indicating that Cut3ΔNC–Cut14ΔN that did not promote DNA reannealing was still able to associate with cruciform DNA. The full-length Cut3–Cut14 complex was used as control.