. Author manuscript; available in PMC: 2014 Mar 2.

Published in final edited form as: Virology. 2011 Oct 21;421(2):141–148. doi: 10.1016/j.virol.2011.08.028

Table 2.

Comparison of helical parameters for extended and contracted sheath of phage T4, ØKZ, and SBP8a.

Sheath	T4			ØKZ			SBP8a
Sheath	Extended	Contracted	Relationship between the two states	Extended	Contracted	Relationship between the two states	Extended	Contracted	Relationship between the two states
Length (Å)	925	420	Shortens by 65%	1593	^a	^a	1786	953	Shortens by 47%
Diameter (Å)	240	330	Broadens by 38%	^a	^a	^a	195	280	Broadens by 44%
Number of strands	6	6	No change	6	^a	^a	6	6	No change
Number of subunits per helical strand	23	23	No change	44	^a	^a	45	45	No change
Helical pitch (Å)	40.6	16.4	Decreases by 60%	36.2	^a	^a	39.5	19.1	Decreases by 57%
Helical twist	17.2°	32.9°	Increases by 91%	22°	^a	^a	21.7°	31.3°	Increases by 44%
Total twist angle	378.4° (1.05^a2π)	723.8° (2.01^a2π)	Increase by 345.4° (0.96^a2π)	968° (2.69^a2π)	^a	^a	954.8° (2.65^a2π)	1377.2° (3.8^a2π)	Increases by 442.4° (1.15^a2π)

Data absent.