The protein tube is a spline curve that passes through all the
Cs in a protein fragment. Five evenly spaced interpolation
points are found along the curve to break the curve connecting the two
C
s into six line segments. If the first C
is
selected, the first three segments are colored by the color assigned
to that C
. If the second C
is selected, the last
three segments are colored by the color of the second C
. The
nucleic acid tube is constructed in the same manner except that the
phosphate atoms are used.
The two controls set the spline radius and resolution and have the same meaning as they did in the `Bond' control. However, if the bond radius becomes 0 or the bond resolution is 2 or less then the spline is drawn as a simple line. This make moving and rotation the image much faster.
It is possible to pick with the mouse the C which defines the
tube by clicking near the middle of the six tube segments which are
associated with that atom.