New England Biolabs, Inc.

Maurice W Southworth

Francine B Perler

Theodore B Davis

Ming-Qun Xu

James C Samuelson

Donald G Comb

Christopher J Noren

Elisabeth A Raleigh

William E Jack

Robert A Hodges

Eric E Adam

Shaorong S Chong

Compositions and methods are provided for expression of a toxic protein in a host cell preferably a bacterial host cell where at least one T7 RNA polymerase gene Is contained on the host cell chromosome and one or more genes encoding a T7 RNA polymerase inhibitor is located on an F' plasmid or on the chromosome.

Expression of toxic genes in vivo in a non-natural host

The present invention is directed to modified proteins and methods of their production. The modified proteins comprise a controllable intervening protein sequence (CIVPS) inserted into or adjacent a target protein, the CIVPS being capable of excision from or cleavage of the modified protein under predetermined conditions in cis or in trans, i.e., increase in temperature, exposure to light, unblocking of amino acid residues by dephosphorylation, treatment with chemical reagents or deglycosylation. If desired, the modified protein can be subjected to these conditions. The CIVPS may also be inserted into a region that substantially inactivates target protein activity. The CIVPS may be used in a number of applications including purification of the target protein in a one-step protocol.

Modified proteins comprising controllable intervening protein sequences

The present invention is directed to an extremely thermostable enzyme. More specifically, the invention is directed to a thermostable DNA polymerase 9.degree.N-7, as well as the recombinant form of 9.degree.N-7. In another embodiment, there is provided a method for mutagenizing the exo motif I of the 3'-5' exonuclease DNA polymerases from the native conserved DXE in the 3'-5' exo motif I DNA segment to DXD or AXA.

Thermostable DNA polymerase from 9.degree.N-7 and methods for producing

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Newburyport, MA, United States of America

Maurice W Southworth