Chiron Corporation

Cetus Corporation

Cetus Oncology Corporation

Michael Piatak, Jr

Glenn T Horn

Walter J Laird

L L Houston

Anne W Emerick

Julie A Lane

DNA sequences encoding full length precursor proteins, which proteins contain both A and B portions of two ricin isotoxins and ricin agglutinin, as well as the linker regions have been determined. These DNAs or portions or modifications thereof are expressed in recombinant hosts to obtain the desired proteins or proteins which can readily converted thereto. One of the ricin isotoxins may be related to ricin E.

Recombinant ricin toxin

Recombinant vectors and methods for constructing ricin B are disclosed. The coding sequence for ricin B was cloned, disposed in suitable expression vectors and produced free of components normally accompanying this peptide. In addition, a novel means of reconstructing missing portions of coding sequence, and certain improvements in messenger RNA purification are disclosed.

DNA sequence construction

Recombinant lectins

Recombinant ricin toxin fragments

Ricin B muteins, ricin and ricin precursors having at least one amino acid of at least one galactoside binding site altered to decrease the binding of ricin B to galactosides are claimed. DNA sequences encoding the ricin B muteins, ricin and ricin precursor in which the B chain thereof is the ricin B mutein are claimed. Recombinant expression vectors effective in expressing the DNA sequences of the ricin B muteins, ricin and ricin precursors are claimed. Host cells transformed with the foregoing expression vectors are also claimed. Conjugates comprising binding moieties such as antibodies, hormones, and lymphokines bound to the ricin B mutein and ricin wherein the B chain thereof is the mutein is also claimed.

A system for expression of coding sequences for desired heterologous proteins in procaryotic hosts whereby the protein is produced intracellularly in soluble, biologically active form, is disclosed. The expression is obtained by ligation of the coding sequence downstream of, and proximally to, but out of reading frame with, the terminated leader encoding sequence for a secreted bacterial protein, such as alkaline phosphatase. The resultant proteins are influenced by the leader sequence codons to effect the desired three-dimensional conformation, but not to effect secretion.

Growing community of inventors

Walnut Creek, CA, United States of America

Michael Piatak, Jr