Back to main article: Interactome under construction

In November, Pacific Biosciences of Menlo Park, California, commercially released its third-generation DNA-sequencing platform, based on its single-molecule, real-time (SMRT) technology. A single DNA polymerase bound to a DNA template is attached to a tiny chamber illuminated by lasers, and nucleotides labelled with coloured fluorophores are introduced to it. As the polymerase incorporates them, each base is held for a few microseconds, while the fluorophore emits coloured light corresponding to the base identity. SMRT technology could also be used to analyse biomolecules other than DNA, and could become a common tool for detecting protein interactions, with some unique features. “This technology can detect relatively weak interactions,” says Jonas Korlach, a scientific fellow at Pacific Biosciences, adding that it could pick out interactions that happen so quickly that they can't be identified by current methods.

Future SMRT systems could reveal interactions. Credit: PACIFIC BIOSCIENCES

As a step towards such applications, Joseph Puglisi, a structural biologist at Stanford University School of Medicine in California, and his group, with scientists at Pacific Biosciences, observed transfer RNAs binding to single ribosomes in real time13. In an unpublished follow-up, Puglisi's group has used SMRT technology to watch interactions between transfer RNAs, ribosomes and protein factors to determine how the translation machinery synthesizes proteins. “We have just seen the tip of the iceberg in terms of applications,” says Korlach.

L.B.