Modified Biotin-Binding Proteins for Robust Single Molecule Immobilization
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Solution Overview
Problem
Current methods for single molecule analysis, such as DNA and RNA sequencing, face challenges in robustly immobilizing individual molecules on solid supports due to the high sensitivity and specificity required, which is not adequately addressed by existing biotin-binding proteins like streptavidin.
Innovation Solution
Development of modified biotin-binding proteins with covalently attached sulfonate moieties and amino acid substitutions that decrease the calculated net charge, enhancing their immobilization capabilities on solid supports, particularly in nanoscale wells for nucleic acid sequencing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional biotin-binding proteins like streptavidin are used for immobilization, then high affinity binding to biotin is achieved, but robust immobilization of individual molecules on solid supports is not sufficiently improved
Solution Approach 1:
The patent modifies the charge parameters of biotin-binding proteins by introducing amino acid substitutions and covalently attaching sulfonate moieties. These parameter changes alter the protein's electrostatic properties to enhance its ability to robustly immobilize individual molecules on solid supports, specifically improving performance in single molecule analysis applications
Solution Approach 2:
The patent creates composite modified biotin-binding proteins by combining conventional biotin-binding proteins with sulfonate moieties and engineered amino acid sequences. This composite approach integrates the high affinity biotin binding capability with enhanced electrostatic interactions to achieve robust immobilization of individual molecules
2Measurement precision
If biotin labeling methods are used to label and immobilize molecules, then specific binding is achieved, but robust immobilization of individual molecules is not adequately addressed
Solution Approach 1:
The patent modifies the electrostatic parameters of biotin-binding proteins through amino acid substitutions and sulfonate moiety attachment. These parameter changes enhance the protein's ability to maintain specific binding while achieving robust immobilization of individual molecules, resolving the contradiction between specificity and robustness
3Productivity
If single molecule analysis is performed, then high sensitivity and throughput are achieved, but robust immobilization of individual molecules becomes challenging
Solution Approach 1:
The patent modifies the charge and electrostatic properties of biotin-binding proteins to enhance their ability to robustly retain individual molecules during high-throughput single molecule analysis, enabling both high productivity and reliable molecule retention simultaneously
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified biotin-binding proteins provide improved immobilization and retention of nucleic acids and polymerases, enabling more efficient and reliable single molecule analysis with enhanced stability and specificity.
Implementation Method 1
These methods also rely upon proteins such as avidin or streptavidin, which bind very tightly and specifically to biotin
Implementation Method 2
the biotin-binding protein comprises one or more amino acid substitutions that decrease its calculated net charge relative to a parental biotin-binding protein
Data Source
AI summary
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.