Wyoming scientists identify two new glycoproteins in the web glue from the golden orb weaving spider.
sticky substance in spider webs may lead to the development of a new generation
of bio-based adhesives and glues that could replace some petroleum-based
While would-be goblins and ghosts were preparing to drape
synthetic spider webs over doorways and trees this past Halloween, scientists
reported on a long-standing mystery about real spider webs: the secret of
spider web glue. The findings are an advance toward a new generation of
bio-based adhesives and glues - “green” glues that replace existing
petroleum-based products for a range of uses. A report on the study was
published in the October 2009 issue of the American Chemical Society's monthly
Omer Choresh and colleagues noted that heavy research has been conducted on
spider web silk, which rivals steel in its strength. However, scientists know
comparatively little about web glue, which coats the silk threads and is among
the world’s strongest biological glues. Past studies revealed that spiders make
web glue from glycoproteins, or proteins with bits of sugar attached.
The scientists analyzed web glue from the golden orb weaving spider, noted for
spinning intricate webs. They identified two new glycoproteins in the glue and
showed that domains of these proteins were produced from opposite strands of
the same DNA.
“Once the cloned genes are over-expressed in systems such as insect or
bacterial cell cultures, large-scale production of the glycoprotein can be used
to develop a new bio-based glue for a variety of purposes,” the report noted.
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Source: American Chemical Society
SIDEBAR: About the Study
various silks that make up the web of the orb web spider have been studied
extensively. However, success in prey capture depends as much on the web glue
as on the fibers. Spider silk glue is an aqueous solution secreted from the orb
weaving spider’s aggregate glands that coats the spiral prey-capturing threads
of their webs. Studies identified the major component of the glue as
microscopic nodules made of a glycoprotein. This study describes two newly
discovered proteins that form the glue-glycoprotein of the golden orb weaving
spider Nephila clavipes
. Results demonstrate that both
proteins contain unique 110 amino acid repetitive domains that are encoded by
opposite strands of the same DNA sequence. Thus, the genome of the spider
encodes two distinct yet functionally related genes by using both strands of an
identical DNA sequence. Moreover, the closest match for the nonrepetitive
region of one of the proteins is chitin binding proteins. The web glue appears
to have evolved to a substantial level of sophistication, matching that of the
spider silk fibers.