Harvard College

University of Texas System

University of Washington

Gro Biosciences Inc.

Daniel J Mandell

George M Church

Christopher John Gregg

Marc J Lajoie

Justin Feng

David Baker

Andrew D Ellington

Ross Thyer

Christine Elaine Tinberg

Peter Benjamin Stranges

Stanley Fields

Benjamin Ward Jester

Peter B Stranges

Rajagopal Chari

Xavier Rios Villanueva

Biosensors for small molecules can be used in applications that range from metabolic engineering to orthogonal control of transcription. Biosensors are produced based on a ligand-binding domain (LBD) using a method that, in principle, can be applied for any target molecule. The LBD is fused to either a fluorescent protein or a transcriptional activator and is destabilized by mutation such that the fusion accumulates only in cells containing the target ligand. The power of this method is illustrated by developing biosensors for digoxin and progesterone. Addition of ligand to cells expressing a biosensor activates transcription in yeast, mammalian cells and plants, with a dynamic range of up to about 100-fold or more. The biosensors are used to improve the biotransformation of pregnenolone to progesterone in yeast and to regulate CRISPR activity in mammalian cells. This work provides a general methodology to develop biosensors for a broad range of molecules.

Small molecule biosensors

Provided herein is a stabilized DNase I polypeptide containing a non-standard amino acid that maintains enzymatic activity even under harsh conditions, such as reducing environments. The stabilized DNase I polypeptide has enzymatic activity in reducing environments that is higher than a corresponding DNase I polypeptide without the non-standard amino acids under the same conditions. Also provided herein are polynucleotides encoding the stabilized DNase I polypeptide, cells for expressing and/or producing the stabilized DNase I polypeptide, and methods of use of the stabilized DNase I polypeptide.

Non-standard amino acid containing compositions and uses thereof

Polypeptides that fold into biologies are stabilized by diselenide bonds between selenocysteine amino acids. Methods to produce such polypeptides in genomically recoded organisms (GRO) can be scaled up for industrial production. Since diselenides have the same geometric bond angles and torsions as disulfides, as well as very similar bond lengths, they can be substituted into polypeptides without disrupting the three dimensional structure of the polypeptides. Diselenides render the polypeptides resistant to reduction when they are exposed to blood serum or to reducing components of blood serum or to reducing components components within cells.

Production of seleno-biologics in genomically recoded organisms

A method of making a polypeptide including at least one covalent bond between a pair of reactive side chains of corresponding amino acids, wherein the covalent bond is insensitive to reduction is provided including genetically modifying a genomically recoded organism to express a corresponding synthetase, tRNA or synthetase/tRNA pair for translating mRNA encoding the corresponding amino acids having the reactive side chains into the polypeptide and to express the polypeptide including the at least one pair of the reactive side chains wherein the reactive side chains are oriented near one another when the expressed polypeptide is in a folded configuration, wherein the reactive side chains react to form the covalent bond that is insensitive to reduction.

Methods of making polypeptides with non-standard amino acids using genomically recoded organisms

Recombinant cells and recombinant organisms persistently expressing nonstandard amino acids (NSAAs) are provided. Methods of making recombinant cells and recombinant organisms dependent on persistently expressing NSAAs for survival are also provided. These methods may be used to make safe recombinant cells and recombinant organisms and/or to provide a selective pressure to maintain one or more reassigned codon functions in recombinant cells and recombinant organisms.

Recombinant cells and organisms having persistent nonstandard amino acid dependence and methods of making them

Disclosed is a biosensor engineered to conditionally respond to the presence of specific small molecules, the biosensors including conditionally stable ligand-binding domains (LBDs) which respond to the presence of specific small molecules, wherein readout of binding is provided by reporter genes or transcription factors (TFs) fused to the LBDs.

Biosensors engineered from conditionally stable ligand-binding domains

Growing community of inventors

Brookline, MA, United States of America

Daniel J Mandell