The
plait is a relatively simple
protein fold, consisting of a four
stranded antiparallel
beta sheet and packing against a pair of
helices. Here is a crude
ascii diagram of the topology :
_____________ _____________ ______________
/ __________ \ / ___________ \ / ____________ \
/ / \ \ / / \ \ / / \ \
/ / \ \ / / \ \ / / \ \
/ / \ \ / / \ \/ / \ \
| | \ \ / / \ \ / \ \
| | \ \ / / \ \ \ \
| | \ \/ / \ \ \ \
| | \ \ / / \ \ \ \
| | \ \ / / \ \ \ \
| | / \ \ / / \ \ \ \
\ \ / /\ \ / / \ \ \C \
\ \ / / \ \ / / \ \
\ \ / / \ \ / / \ \
\ \__________/ / \ \_________/ / \ \
\_____________/ \____________/ \N\
Okay, so it's not very good, but from
N to C it goes strand, helix, strand,
hairpin , strand, helix, and strand. Or NEhEeHeC in TOPS notation. Not that anyone cares.
A good example of this fold is 2bop - a DNA binding protein.
If I was to guess at how this fold assembles, I would say that the hairpin might form first, and then the terminal pair of strands. Then the two half sheets would fold in opposite directions across the pair of helices.
Of course, it is bound to not be as simple as this in reality.