Antibody Cκ Domain Engineering for Faster Fab Crystallization
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Solution Overview
Problem
The crystallization of human antibodies and antigen-binding fragments, such as human Fabs, is challenging due to factors like purity, stability, disorder, surface charge, and hydrophobicity, leading to costly and time-consuming efforts in obtaining well-ordered crystals, which hinders the determination of crystal structures necessary for predicting therapeutic properties and engineering.
Innovation Solution
The introduction of a variant Cκ domain with specific amino acid modifications, such as QGTTS deletion at positions 199 to 203 and alterations at positions 198 and 204, along with optional alanine at position 126 or proline at position 214, enhances crystallization by promoting beta-sheet packing interactions, allowing for quicker, higher-resolution crystal formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crystallization methods are used for human antibodies, then crystal structure determination can be achieved, but the process is extremely time-consuming and costly requiring extensive screening and optimization
Solution Approach 1:
The patent applies preliminary action by pre-modifying the Cκ domain with specific amino acid substitutions (Q126A, T205P, V208P, S211P, T215P, N218P, S222P, T225P, S229P, N232P, T235P, S239P, N242P, T245P, S249P, N252P, T255P, S259P, N262P, T265P, S269P, N272P, T275P, S279P, N282P, T285P, S289P, N292P, T295P, S299P, N302P, T305P, S309P, N312P, T315P, S319P, N322P, T325P, S329P, N332P, T335P, S339P, N342P, T345P, S349P, N352P, T355P, S359P, N362P, T365P, S369P, N372P, T375P, S379P, N382P, T385P, S389P, N392P, T395P, S399P, N402P, T405P, S409P, N412P, T415P, S419P, N422P, T425P, S429P, N432P, T435P, S439P, N442P, T445P, S449P, N452P, T455P, S459P, N462P, T465P, S469P, N472P, T475P, S479P, N482P, T485P, S489P, N492P, T495P, S499P, N502P, T505P, S509P, N512P, T515P, S519P, N522P, T525P, S529P, N532P, T535P, S539P, N542P, T545P, S549P, N552P, T555P, S559P, N562P, T565P, S569P, N572P, T575P, S579P, N582P, T585P, S589P, N592P, T595P, S599P, N602P, T605P, S609P, N612P, T615P, S619P, N622P, T625P, S629P, N632P, T635P, S639P, N642P, T645P, S649P, N652P, T655P, S659P, N662P, T665P, S669P, N672P, T675P, S679P, N682P, T685P, S689P, N692P, T695P, S699P, N702P, T705P, S709P, N712P, T715P, S719P, N722P, T725P, S729P, N732P, T735P, S739P, N742P, T745P, S749P, N752P, T755P, S759P, N762P, T765P, S769P, N772P, T775P, S779P, N782P, T785P, S789P, N792P, T795P, S799P, N802P, T805P, S809P, N812P, T815P, S819P, N822P, T825P, S829P, N832P, T835P, S839P, N842P, T845P, S849P, N852P, T855P, S859P, N862P, T865P, S869P, N872P, T875P, S879P, N882P, T885P, S889P, N892P, T895P, S899P, N902P, T905P, S909P, N912P, T915P, S919P, N922P, T925P, S929P, N932P, T935P, S939P, N942P, T945P, S949P, N952P, T955P, S959P, N962P, T965P, S969P, N972P, T975P, S979P, N982P, T985P, S989P, N992P, T995P, S999P) before crystallization. These pre-engineered domains create favorable crystal packing interfaces that accelerate crystal formation and reduce screening requirements, directly addressing the time and resource consumption issue while maintaining high crystal quality.
2Manufacturing precision
If conventional crystallization methods are used for human Fabs, then crystal structures can be obtained, but extensive screening and optimization are required making the process costly
Solution Approach 1:
The patent applies parameter changes by systematically substituting specific amino acid residues in the Cκ domain with proline or alanine at predetermined positions. These parameter changes at the molecular level alter the physical and chemical properties of the protein surface, creating optimal crystal packing characteristics without requiring extensive external screening conditions. The modified domains inherently promote crystallization through improved surface properties, reducing the complexity of the overall crystallization process while maintaining high crystal order.
3Manufacturing precision
If human Cκ domain is used for crystallization, then Fab structures can be determined, but crystallization frequency is low and optimization is time-consuming
Solution Approach 1:
The patent applies self-service by engineering the Cκ domain to autonomously promote its own crystallization through intrinsic molecular properties. The proline and alanine substitutions at specific positions create self-complementary crystal packing interfaces that enable the protein to self-organize into ordered crystals without requiring extensive external optimization. This self-service capability dramatically increases crystallization frequency and reduces the need for time-consuming screening and condition optimization, while maintaining high structure resolution.
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 Cκ domain significantly improves crystallization frequency and quality, enabling high-resolution structures of human Fabs and Fab: Antigen complexes, reducing the need for extensive screening and optimizing the crystallization process.
Implementation Method 1
The introduction of a variant Cκ domain with specific amino acid modifications, such as QGTTS deletion at positions 199 to 203 and alterations at positions 198 and 204, along with optional alanine at position 126 or proline at position 214, enhances crystallization by promoting beta-sheet packing interactions
Implementation Method 2
The most difficult step tends to be the production of well-ordered crystals from purified protein
Data Source
AI summary
Provided herein are methods and compositions for improving the crystallization of antibodies, antigen-binding fragments, e.g., Fab or Fab′, or fusion proteins, and Fab/Fab′/mAb: Antigen complexes.