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Archive - Oct 21, 2009

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Spider Web Glue May Prove Basis for New Bio-Based Adhesives

New studies on the glue that coats the silk of spider webs may lead to the development of “green” glues that can replace existing petroleum-based products for a range of uses. Scientists at the University of Wyoming 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. The report appeared in the October 12 issue of Biomacromolecules published by the American Chemical Society. [Press release] [Biomacromolecules abstract]

SS DNA-Binding Protein Is Dynamic and Critical to DNA Repair

Researchers report that a single-stranded DNA-binding protein (SSB), once thought to be a static player among the many molecules that interact with DNA, actually moves back and forth along single-stranded DNA, gradually allowing other proteins to repair, recombine, or replicate the strands. In a series of experiments in E. coli, the researchers showed that SSB diffuses randomly back and forth along single-stranded DNA, and that this movement is independent of the sequence of nucleotides that make up the DNA. They also found that an important DNA repair protein in E. coli, RecA, grows along the single-stranded DNA in tandem with the movement of SSB. As the RecA protein extends along the DNA strand, it prevents the backward movement of the SSB. The researchers also found that SSB can "melt" small hairpin loops that appear in single-stranded DNA, straightening them so that the RecA protein can bind to and repair them. In this way, SSB modulates the activity of RecA and other proteins that are involved in DNA repair, recombination, and replication. "SSB may be a master coordinator of all these important processes," said Dr. Taekjip Ha, senior author of the study, which is reported in the October 22 issue of Nature. [Press release] [Nature News & Views] [Nature abstract]