Mimivirus GGT Enzyme Expression for Recombinant Collagen Glycosylation
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Solution Overview
Problem
Current bacterial expression systems are unable to produce recombinant human collagen effectively due to the difficulty in expressing active human collagen modifying enzymes, particularly glycosyltransferases, which are essential for post-translational modifications of collagen.
Innovation Solution
Identification and expression of mimivirus-derived collagen modifying enzymes, such as galactosylhydroxylysyl glucosyltransferase (GGT), in bacterial cells like Escherichia coli, enabling the production of recombinant human collagen with specific post-translational modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If human collagen modifying enzymes are expressed in bacterial cells, then recombinant human collagen with post-translational modifications can be produced, but the enzymes cannot be effectively expressed in bacteria due to system incompatibility
Solution Approach 1:
The patent uses a two-step intermediary approach: first, mimivirus enzymes are expressed in bacteria to modify collagen precursors; second, the modified collagen is processed in mammalian cells to complete post-translational modifications. This intermediary system bridges the gap between bacterial expression capabilities and human collagen modification requirements.
Solution Approach 2:
The patent divides the collagen production process into separate stages: bacterial cells handle initial collagen synthesis and mimivirus enzyme modifications, while mammalian cells perform final processing and maturation. This segmentation allows each system to operate within its capabilities while achieving the overall goal of producing fully modified human collagen.
2Reliability
If animal-derived collagen is used, then collagen with natural post-translational modifications is available, but pathogen contamination risk and species incompatibility issues arise
Solution Approach 1:
The patent creates a synthetic copy of animal collagen production by using bacterial cells to express human collagen genes with mimivirus enzymes, then completing maturation in mammalian cells. This copying approach produces humanized collagen that mimics natural animal-derived collagen structure and function while eliminating pathogen contamination risks associated with direct animal sourcing.
3Productivity
If bacterial expression system is used for collagen production, then scalability and cost-effectiveness are improved, but endogenous collagen contamination from bacterial cells occurs
Solution Approach 1:
The patent extracts and removes endogenous bacterial collagen through selective digestion and purification steps. By using specific enzymes that recognize human collagen structures but not bacterial collagen, the system selectively removes contaminating bacterial collagen while preserving the recombinant human collagen product.
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 expression of mimivirus-derived enzymes allows for the production of recombinant human collagen with accurate post-translational modifications, facilitating its use in tissue culture and biomedical applications, including as diagnostic and therapeutic reagents for conditions like Rheumatoid Arthritis.
Implementation Method 1
contacting mimiviral enzymes and/or derivatives and/or mutants thereof with a collagen, such as a human collagen, whereby, the collagen is then post-translationally modified by the activity of the enzyme
Implementation Method 2
identification of collagen modifying enzymes in the mimiviral genome... galactosylhydroxylysyl glucosyltransferase (GGT)... enabling the production of recombinant human collagen with specific post-translational modifications
Data Source
AI summary
Humans and Acanthamoeba Polyphaga Mimivirus share numerous homologous genes, including collagens and collagen-modifying enzymes. To explore the homology, a genome-wide comparison was performed between human and mimivirus using DELTA-BLAST (Domain Enhanced Lookup Time Accelerated BLAST) and identified 190 new mimiviral proteins that share homology with 1236 human proteins. To gain functional insights into mimiviral proteins, the human protein homologs were organized into Gene Ontology (GO) and REACTOME pathways to build a functional network. Collagen and collagen-modifying enzymes form the largest subnetwork with most nodes. Further analysis of this subnetwork identified a putative collagen glycosyltransferase R699. Protein expression test suggested that R699 is highly expressed in E coli, unlike the human collagen-modifying enzymes. Enzymatic activity assays showed that R699 catalyzes the conversion of galactosyl-hydroxylysine to glucosyl-galactosyl-hydroxylysine on collagen using UDP-glucose as a sugar donor, suggesting R699 is a mimiviral collagen galactosylhydroxylysyl glucosyltransferase (GGT). Structural study of R699 produced the first crystal structure of a collagen GGT with uridine diphosphate glucose (UDP-Glc). Sugar moiety of the UDP-Glc resides in a previously unrecognized pocket. Mn2+ coordination and nucleoside-diphosphate binding site are conserved among GGT family members and critical for R699's collagen GGT activity. To facilitate further analysis of human and mimiviral homologous proteins, we presented an interactive and searchable genome-wide comparison app for quickly browsing of human and Acanthamoeba Polyphaga Mimivirus homologs, which is available at RRID Resource ID: SCR_022140 or guolab.shinyapps.io/app-mimivirus-publication/.