The invention concerns novel streptavidin muteins and their use for determination, isolation or purification of proteins under denaturing conditions. In one embodiment such a mutein has an Cys residue at sequence position 127 of the wild-type sequence of streptavidin and comprises at least one mutation in the region of the amino acid positions 115 to 121 with reference to the amino acid sequence of wild type streptavidin.

The invention concerns novel streptavidin muteins and their use for determination, isolation or purification of proteins under denaturing conditions. In one embodiment such a mutein has an Cys residue at sequence position 127 of the wild-type sequence of streptavidin and comprises at least one mutation in the region of the amino acid positions 115 to 121 with reference to the amino acid sequence of wild type streptavidin.

Provided herein, in some aspects, are polypeptide monomers comprising an angiotensin-converting enzyme 2 (ACE2) ectodomain and an oligomerization domain. Also provided herein are oligomeric complexes comprising ACE2 monomers. Methods of using such to monomers and oligomeric complexes for the diagnosis, prevention, and treatment of viral infections such as the coronavirus are also provided.

Provided herein, in some aspects, are polypeptide monomers comprising an angiotensin-converting enzyme 2 (ACE2) ectodomain and an oligomerization domain. Also provided herein are oligomeric complexes comprising ACE2 monomers. Methods of using such to monomers and oligomeric complexes for the diagnosis, prevention, and treatment of viral infections such as the coronavirus are also provided.

Described herein are biological devices and methods for using the same to produce oxidized zinc. The biological devices include microbial cells transformed with a DNA construct containing genes for producing a zinc-related protein, an alkaline phosphatase, and an alcohol dehydrogenase. In some instances, the biological devices also include a gene for lipase. The oxidized zinc compositions produced herein have numerous applications.

Compositions comprising covalently modified and mutated biotin-binding proteins, particularly biotin-binding proteins having a negative charge at physiological pH, are provided. Methods of producing such proteins are also provided, as are methods of immobilizing, sequencing, and making nucleic acids employing such proteins.

Compositions comprising covalently modified and mutated biotin-binding proteins, particularly biotin-binding proteins having a negative charge at physiological pH, are provided. Methods of producing such proteins are also provided, as are methods of immobilizing, sequencing, and making nucleic acids employing such proteins.

An object of this invention is to provide a streptavidin mutant reduced in affinity to the naturally-occurring biotin, and to provide a modified biotin which shows a high affinity to such streptavidin mutant reduced in affinity to the naturally-occurring biotin. This invention can provide a compound composed of a dimer of modified biotin, a streptavidin mutant, angsd usage of them.

An object of this invention is to provide a streptavidin mutant reduced in affinity to the naturally-occurring biotin, and to provide a modified biotin which shows a high affinity to such streptavidin mutant reduced in affinity to the naturally-occurring biotin. This invention can provide a compound composed of a dimer of modified biotin, a streptavidin mutant, angsd usage of them.

The present invention relates to methods for screening for the presence of a biosynthetic gene cluster (BGC) in a cell, via the identification of proximal positive 5 regulatory genes, e.g. large ATP-binding regulators of the LuxR family (LAL) genes.