Sent: Tuesday, January 20, 2004 8:39 AM
To: Schloss, Jeff (NIH/NHGRI)

As an informal update, I can say that we have made huge progress on: (1)
a new way to use the micron-scale beads without an emulsion step
(involving changes in surfaces and polymers just as recommended in the
CEGS reviewers), (2) We have nearly doubled our accurate read-lengths
again (to 28 cycles), (3) developed a kinetic model that has pointed a
way to even much longer read-lengths (mainly by changing the
polymerase). (4) We have hit upon a structural model for how the
reversible terminators (Cy3-SS-dNTP) might work (where the two cyanine
rings and two sulfates anions are in a configuration mimicing and
competing with the WC-basepair and phosphate anions (normally in the
polymerase active site). (5) To test this, we are starting on the
crystal structure of one of the terminators complexed with T7 DNA
polymerase (in collaboration with Tom Ellenberger and the Genovoxx
group) which should be helpful for both polony sequencing and various
"pure"-single molecule fluorescent sequencing methods.