Methanotrophic Bacteria Nucleic Acid Vectors for Protein Expression
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Solution Overview
Problem
Genetic manipulation of methanotrophic bacteria is challenging due to a lack of robust protocols and tools such as vectors, expression cassettes, and suitable promoters, with issues like methanotroph-incompatible antibiotic resistance markers, inappropriate restriction sites, and poor protein expression.
Innovation Solution
Development of non-naturally occurring nucleic acid molecules with functional promoters and ribosomal binding sequences specific to methanotrophic bacteria, including constitutive and inducible promoters, and vectors like pCAL that facilitate reliable genetic manipulation by improving transformation efficiency and target gene expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional vectors and expression cassettes are used for genetic manipulation of methanotrophic bacteria, then transformation can be attempted, but protein expression is poor and transformation efficiency is low
Solution Approach 1:
The patent optimizes the ribosome binding site sequence and its spacing relative to the start codon to improve translation initiation efficiency. By modifying these parameters of the expression cassette, the patent achieves significantly improved protein expression levels in methanotrophic bacteria.
Solution Approach 2:
The patent introduces a specific ribosome binding site sequence as an intermediary element between the promoter and the gene of interest. This intermediary component facilitates efficient ribosome recruitment and translation initiation, thereby improving protein expression without affecting other aspects of the transformation system.
2Productivity
If constitutive promoters are used, then continuous expression occurs, but uninduced expression levels are too high causing metabolic burden
Solution Approach 1:
The patent replaces static constitutive promoters with dynamic inducible promoters that can adjust their activity state. The promoter transitions from a repressed state (low expression) to an induced state (high expression) in response to specific environmental signals, allowing the system to adapt expression levels to physiological conditions and minimize metabolic burden when induction is not required.
Solution Approach 2:
The patent employs promoter constructs with operator sequences and repressor proteins that preemptively prevent transcription initiation before induction is needed. This preliminary repression action blocks unwanted expression, and only when the appropriate inducer is present does the repression is relieved, allowing productive expression to occur.
3Productivity
If available promoters and ribosomal binding sequences are used, then some expression occurs, but expression levels are insufficient for practical applications
Solution Approach 1:
The patent develops a universal expression cassette design that can be applied to multiple different genes and experimental conditions in methanotrophic bacteria. The optimized ribosome binding site and promoter combinations create a multi-functional tool that works across different genetic contexts, eliminating the need to develop separate expression systems for each application.
Data Source
AI summary
The present disclosure provides nucleic acids and vectors for use with methanotrophic bacteria. Related host cells and methods for using such nucleic acids and vectors for expressing polypeptides or other genetic manipulation of methanotrophic bacteria are also provided. In one aspect, the present disclosure is directed to a non-naturally occurring nucleic acid molecule, comprising (1) a promoter that is functional in a methanotrophic bacterium, and (2) a native or altered methanol dehydrogenase (MDH) ribosomal binding sequence, provided that when the promoter is an MDH gene promoter, the nucleic acid comprises an altered MDH ribosomal binding sequence.