From Wikipedia,
the free encyclopedia.
A biopolymer is a
polymer found in nature.
Starch,
proteins and
peptides, and
DNA and
RNA are all examples of
biopolymers, in which the monomer
units, respectively, are
sugars,
amino acids, and
nucleic acids. The exact
chemical composition and the
sequence in which these units are
arranged is called the polymer's
primary structure. Many
biopolymers spontaneously "fold"
into characteristic shapes, which
determine their biological
functions and depend in a
complicated way on their primary
structures.
Structural biology is the
study of the shapes of
biopolymers.
The convention for a protein is
to list its constituent
amino acid residues as they
occur from the amino terminus to
the carboxylic acid terminus. The
convention for a nucleic acid
sequence is to list the
nucleotides as they occur from
the 5' end to the 3' end of the
polymer chain, where 5' and 3'
refer to the numbering of carbons
around the ribose ring which
participate in forming the
phosphate diester linkages of the
chain. Such a sequence is called
the
primary structure of the
biopolymer.
There are a number of
biophysical techniques for
determining sequence information.
Protein sequence can be determined
by
Edman degradation, in which
the N-terminal residues are
hydrolyzed from the chain one at a
time, derivatized, and then
identified. Mass
spectrometer techniques can
also be used. Nucleic acid
sequence can be determined using
gel
electrophoresis and capillary
electrophoresis. Lastly,
mechanical properties of these
biopolymers can often be measured
using
optical tweezers or
atomic force microscopy.
Some biopolymers- such as
polylactic acid and
poly-3-hydroxybutyrate can be
used as plastics, replacing the
need for
polystyrene or
polyethylene based plastics.
See also
