Table 1.

AFM analysis of molecules from reactions containing a 660-bp DNA fragment alone or in the presence of DNA-PK components

	DNA	+Ku	+DNA-PK	DNA-PK + ATP
Looped	2.3%	17.3%	16.5%	11.2%
	(7)	(38)	(43)	(31)
Multi-DNA complex	1.3%	5.5%	4.6%	4.7%
	(4)	(12)	(12)	(13)
Linear	96.4%	77.3%	78.8%	84.1%
	(292)	(170)	(205)	(233)
n	303	220	260	277

For statistical analysis, reactions were mounted unfixed and examined by AFM. The images were scored for the presence of linear, looped, or multiple DNA complexes. Reactions contained a 660-bp linear DNA fragment either alone (DNA), or in the presence of recombinant Ku (+Ku), recombinant Ku and DNA-PKcs (+DNA-PK), or recombinant Ku and DNA-PKcs plus ATP (DNA-PK + ATP). The percentage of reaction totals are followed by the number of molecules observed in parentheses.