TABLE 2.

Complementation of T4 phage by gp2 in vitro^a

Line	Mixture	Total phage	2+ phage	2+/total ratiob
1	H+ + T+	6.2 × 109 (6.0 × 106)c	6.3 × 109 (6.6 × 106)	1.0 (1.1)
2	H+ + T+ + rgp2	3.2 × 109	2.8 × 109	0.9
3	H− + T−	7.2 × 107 (4.8 × 107)	1.0 × 107 (2.5 × 106)	0.31 (0.05)
4	H− + T− + rgp2	9.2 × 109	1.4 × 109	0.15
5	H− + T+	6.7 × 108 (4.0 × 106)	4.4 × 107 (4.5 × 106)	0.06 (1.1)
6	H− + T+ + rgp2	2.9 × 108	2.1 × 107	0.06
7	H+ + T−	2.3 × 109 (2.5 × 106)	2.5 × 109 (2.5 × 106)	1.1 (1.0)
8	H+ + T− + rgp2	1.8 × 109	2.0 × 109	1.1
9	H+(w)d + T−	3.2 × 109 (2.5 × 106)	2.8 × 109 (2.5 × 106)	0.88 (1.0)
10	H+(w) + T− + rgp2	2.2 × 109	2.1 × 109	0.95

^aIncubation was at 30°C for 1 h. 

^bRatio of newly reconstituted phage after subtracting background. (The ratio of the background 2⁺ to total phage is in parentheses.) 

^cBackground values of total phage (phenotypically 2⁺ plus 2⁻) and of 2⁺ phage are calculated from titers of the individual components on JC7735 and on B40SuI, respectively. The background values of the individual components for lines 1, 2, and 5 to 10 are as follows: H⁺, 4.3 × 10⁶ and 4.3 × 10⁶; T⁺, 7.8 × 10⁶ and 8.9 × 10⁶; H⁻, 2.5 × 10⁵ and 2.0 × 10⁵; T⁻, 7.5 × 10⁵ and 6.5 × 10⁵. For lines 3 and 4, the values are as follows: H⁻, 7.5 × 10⁵ and 2.0 × 10⁶; T⁻, 9.6 × 10⁷ and 3.0 × 10⁶. There was no detectable background of phage in the gp2 preparation. 

^dHeads were washed (w) by sedimentation to remove only cytoplasmic gp2 (external to the head).