127. Mizuta, S., Roberts, E. M., and R.
M. Brown, Jr. 1989. A new cellulose synthesizing complex in Vaucheria
hamata and its relation to microfibril assembly. In-Cellulose
and Wood -Chemistry and Technology,
Ed. C. Schuerch. John Wiley and Sons, Inc. N. Y., 659-676.
The relationship between the structure of
a cellulose synthesizing enzyme complex (terminal complex or TC)
and microfibril assembly in the xanthophycean alga Vaucheria
hamata was investigated. Vaucheria TCs are roughly
rectangular and composed of many diagonal rows of particles.
The number of particles in a single diagonal row varies, but sixty
percent of TC rows contain 6-8 particles. The ribbon-like microfibrils
(MFs) of Vaucheria vary in width (21 + 10 nm) and are quite
thin (ca. 1.5-3.0 nm). MFs consist of many small subfibrils (SFs),
about 2 nm wide. From these data, a working model of MF assembly
is suggested in which (1) a ribbon-like cellulose microfibril
is synthesized by a single TC, (2) each subfibril is assembled
along a single diagonal row of particles within the TC; (3) the
number of glucan chains in each SF is correlated with the number
of subunits per diagonal row; and (4) a single particle forms
one (or very few) glucan chains.