Ct. Zhang et R. Zhang, S curve, a graphic representation of protein secondary structure sequence and its applications, BIOPOLYMERS, 53(7), 2000, pp. 539-549
A secondary structure sequence is a symbolic string composed of three kinds
of letters, indicating the helix, strand and coil (including turns), respe
ctively. A graphic representation for this abstract symbolic sequence is pr
oposed here, called the S curve. The S curve is the unique representation f
or a given secondary structure sequence in the sense that the sequence and
the S curve can be uniquely determined from the other. Therefore, the S cur
ve contains all the information that the secondary structure sequence conta
ins. Different geometrical properties of the S curve are studied in details
, which reflect the basic characteristics of the secondary structure sequen
ces. The S curves are used to display, analyze, and compare the secondary s
tructure sequences. Derailed application examples are presented. One advant
age of the S curve methodology is that the main patterns of a given seconda
ry structure sequence can be grasped quickly in a perceivable form. This is
particular useful in rite cases in which longer sequences are involved and
structures of proteins are unknown. (C) 2000 John Wiley & Sons, Inc.