Table 2.

Helical symmetries and cylindrical surface lattice parameters

Type	Subunits/turn	daxial-rise	d−11(d11)	d3(d1)	d−4(d−5)	d7(d6)
Lt	3.6435  ±  0.0003	4.684	51.80	51.88	33.41	39.64
L	5.5148  ±  0.0005	4.772	52.51	51.50	35.56	37.95
R	5.4699  ±  0.0002	4.700	51.79	51.91	33.79	39.33

The second column, Subunits/turn, is the number of subunits per one turn of the one-start (left-handed) helix for the Lt-type and one-start (right-handed) helix for the others, where the significant numbers are the deviation from 3.6667 (=11/3) for the Lt-type and those from 5.5000 (=11/2) for the L- and R-type, which are the numbers of subunits/turn when the 11-start helical lines are exactly parallel to the filament axis. These deviations reflect the tilt angles of the 11-start helices. The estimated error of subunits/turn is relatively large for the L-type, because the layer-line interval is relatively small compared to the layer-line width by the direct beam size. The deduction of the data listed in this table will be described in detail elsewhere. The next column, d_axial-rise, is the axial distance of the subunits and the experimental errors are ±0.005 Å for all of them, which is mainly due to the errors in the specimen-film distances (±0.1%). The other columns are distances from one subunit to neighbors on the cylindrical surface lattices along helical lines specified by the subscripts. The parameters within parentheses are for the L- and R-type except that d₁₁ is for the R-type. These distances are calculated from the values in columns two and three for the surface lattices at the radius of 45 Å. All distances are in Å unit.