MjTET Aminopeptidase Specificity Engineering
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Solution Overview
Problem
The detailed mechanism of polypeptide substrate filtering and guidance to the active site, as well as the amino acid-product expulsion system, remains elusive in TET systems, and there is a need for peptidases with specific activities, particularly for N-terminus aromatic amino acid residues.
Innovation Solution
Characterization of the MjTET protein with enhanced specificity for N-terminus aromatic amino acids, providing a TET protein with broad substrate specificity and identified structural features guiding peptides to catalytic sites, including a mobile loop system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TET complexes are used for peptide degradation, then broad substrate specificity is achieved, but lack of specific activity toward N-terminus aromatic amino acids limits application scope
Solution Approach 1:
The patent applies parameter changes by modifying the enzymatic parameters of TET complexes through site-directed mutagenesis. Specifically, amino acid substitutions in the S1 binding pocket (such as F236Y, F236W, Y238F mutations) alter the chemical properties of the binding site to enhance affinity and catalytic activity toward N-terminus aromatic amino acids while preserving broad substrate specificity for other peptide types.
2Productivity
If TET complexes self-assemble in dodecameric structures, then catalytic efficiency is enhanced, but mechanism of substrate filtering and guidance remains elusive
Solution Approach 1:
The patent applies segmentation by dissecting the TET complex into functional modules: four substrate entry pores formed by junctions of six subunits, and four catalytic chambers each comprising three active sites. This modular segmentation allows independent study of substrate filtering at entry pores versus catalysis in chambers, facilitating mechanistic understanding of how dodecameric structure enhances efficiency while maintaining specificity.
Solution Approach 2:
The patent introduces mobile loop structures as intermediaries that mediate substrate guidance from entry pores to catalytic sites. These loops act as dynamic mediators that facilitate peptide substrate filtering and positioning within the dodecameric structure, enabling detection and measurement of the substrate processing mechanism through their conformational movements.
3Reliability
If multiple TET versions co-exist in cytosol, then functional redundancy is provided, but complexity of cellular peptidase system increases
Solution Approach 1:
The patent applies universality by demonstrating that a single engineered TET complex can perform multiple functions: degrading peptides with N-terminus aromatic amino acids, degrading peptides with other amino acids, and operating under varying pH and temperature conditions. This multi-functionality reduces the need for multiple specialized TET versions in cellular systems while maintaining functional redundancy and reliability.
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 MjTET protein effectively degrades polypeptides and proteins by removing N-terminus aromatic amino acids, demonstrating stability across a wide pH and temperature range, and can be used to valorize industrial wastes and provide new protein sources.
Implementation Method 1
Aminopeptidases represent large class of enzymes that hydrolyze peptide bonds between amino acids in protein or peptide chain
Implementation Method 2
several enzymes from M42 and M18 metallopeptidase families self-assembled in half megadalton complexes made of twelve subunits
Data Source
Figure 1~2C
Figure 3~4
Figure 5A~5B
AI summary
The present invention relates to the use of a TET protein as a N-terminus aromatic amino acid residues specific exopeptidase, said TET protein comprising the amino acid sequence as set forth in SEQ ID NO: 1.