scholarly journals Nanoscale spatial dependence of avidity in an IgG1 antibody

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnieszka Jendroszek ◽  
Magnus Kjaergaard

AbstractAntibodies are secreted proteins that are crucial to recognition of pathogens by the immune system and are also efficient pharmaceuticals. The affinity and specificity of target recognition can increase remarkably through avidity effects, when the antibody can bind a multivalent antigen through more than one epitope simultaneously. A key goal of antibody engineering is thus to optimize avidity, but little is known about the nanoscale spatial dependence of avidity in antibodies. Here, we develop a set of anti-parallel coiled-coils spanning from 7 to 20 nm and validate their structure using biophysical techniques. We use the coiled-coils to control the spacing between two epitopes, and measure how antigen spacing affects the stability of the bivalent antibody:antigen complex. We find a maximal avidity enhancement at a spacing of 13 nm. In contrast to recent studies, we find the avidity to be relatively insensitive to epitope spacing near the avidity maximum as long as it is within the spatial tolerance of the antibody. We thus only see a ~ twofold variation of avidity in the range from 7 to 20 nm. The coiled-coil systems developed here may prove a useful protein nanocaliper for profiling the spatial tolerance and avidity profile of bispecific antibodies.

2019 ◽  
Author(s):  
Agnieszka Jendroszek ◽  
Magnus Kjaergaard

AbstractAntibodies are secreted proteins that are crucial to recognition of pathogens by the immune system and are also efficient pharmaceuticals. The affinity and specificity of target recognition can increase remarkably through avidity effects, when the antibody can bind a multivalent antigen through more than one epitope simultaneously. A key goal of antibody engineering is thus to optimize avidity, but little is known about the nanoscale spatial dependence of avidity in antibodies. Here, we develop a set of anti-parallel coiled-coils spanning from 8-21 nm and validate their structure using biophysical techniques. We use the coiled-coils to control the spacing between two epitopes, and measure how antigen spacing affects the stability of the bivalent antibody:antigen complex. We find a maximal avidity enhancement at a spacing of 14 nm, but only see a ∼2-fold variation of avidity in the range from 8-21 nm. In contrast to recent studies, we find the avidity to be relatively insensitive to epitope spacing near the avidity maximum as long as it is within the spatial tolerance of the antibody. The coiled-coil systems developed here may prove a useful protein nanocaliper for profiling the spatial tolerance and avidity profile of bispecific antibodies.


2000 ◽  
Vol 11 (10) ◽  
pp. 3539-3558 ◽  
Author(s):  
Kenneth C. Wu ◽  
Janine T. Bryan ◽  
Maria I. Morasso ◽  
Shyh-Ing Jang ◽  
Jeung-Hoon Lee ◽  
...  

Many α-helical proteins that form two-chain coiled coils possess a 13-residue trigger motif that seems to be required for the stability of the coiled coil. However, as currently defined, the motif is absent from intermediate filament (IF) protein chains, which nevertheless form segmented two-chain coiled coils. In the present work, we have searched for and identified two regions in IF chains that are essential for the stability necessary for the formation of coiled-coil molecules and thus may function as trigger motifs. We made a series of point substitutions with the keratin 5/keratin 14 IF system. Combinations of the wild-type and mutant chains were assembled in vitro and in vivo, and the stabilities of two-chain (one-molecule) and two-molecule assemblies were examined with use of a urea disassembly assay. Our new data document that there is a region located between residues 100 and 113 of the 2B rod domain segment that is absolutely required for molecular stability and IF assembly. This potential trigger motif differs slightly from the consensus in having an Asp residue at position 4 (instead of a Glu) and a Thr residue at position 9 (instead of a charged residue), but there is an absolute requirement for a Glu residue at position 6. Because these 13 residues are highly conserved, it seems possible that this motif functions in all IF chains. Likewise, by testing keratin IF with substitutions in both chains, we identified a second potential trigger motif between residues 79 and 91 of the 1B rod domain segment, which may also be conserved in all IF chains. However, we were unable to find a trigger motif in the 1A rod domain segment. In addition, many other point substitutions had little detectable effect on IF assembly, except for the conserved Lys-23 residue of the 2B rod domain segment. Cross-linking and modeling studies revealed that Lys-23 may lie very close to Glu-106 when two molecules are aligned in the A22 mode. Thus, the Glu-106 residue may have a dual role in IF structure: it may participate in trigger formation to afford special stability to the two-chain coiled-coil molecule, and it may participate in stabilization of the two-molecule hierarchical stage of IF structure.


2020 ◽  
Author(s):  
Tina Fink ◽  
Bojana Stevović ◽  
René Verwaal ◽  
Johannes A. Roubos ◽  
Rok Gaber ◽  
...  

Abstract The clustering of biosynthetic enzymes is used in nature to channel reaction products and increase the yield of compounds produced by multiple reaction steps. The coupling of multiple enzymes has been shown to increase the biosynthetic product yield. Different clustering strategies have particular advantages as the spatial organization of multiple enzymes creates biocatalytic cascades with a higher efficiency of biochemical reaction. However, there are also some drawbacks, such as misfolding and the variable stability of interaction domains, which may differ between particular biosynthetic reactions and the host organism. Here, we compared different protein-based clustering strategies, including direct fusion, fusion mediated by intein, and noncovalent interactions mediated through small coiled-coil dimer-forming domains. The clustering of enzymes through orthogonally designed coiled-coil interaction domains increased the production of resveratrol in Escherichia coli more than the intein-mediated fusion of biosynthetic enzymes. The improvement of resveratrol production correlated with the stability of the coiled-coil dimers. The coiled-coil fusion-based approach also increased mevalonate production in Saccharomyces cerevisiae , thus demonstrating the wider applicability of this strategy.


2020 ◽  
Author(s):  
Tina Fink ◽  
Bojana Stevović ◽  
René Verwaal ◽  
Johannes A. Roubos ◽  
Rok Gaber ◽  
...  

Abstract The clustering of biosynthetic enzymes is used in nature to channel reaction products and increase the yield of compounds produced by multiple reaction steps. The coupling of multiple enzymes has been shown to increase the biosynthetic product yield. Different clustering strategies have particular advantages as the spatial organization of multiple enzymes creates biocatalytic cascades with a higher efficiency of biochemical reaction. However, there are also some drawbacks, such as misfolding and the variable stability of interaction domains, which may differ between particular biosynthetic reactions and the host organism. Here, we compared different protein-based clustering strategies, including direct fusion, fusion mediated by intein, and noncovalent interactions mediated through small coiled-coil dimer-forming domains. The clustering of enzymes through orthogonally designed coiled-coil interaction domains increased the production of resveratrol in Escherichia coli more than the intein-mediated fusion of biosynthetic enzymes. The improvement of resveratrol production correlated with the stability of the coiled-coil dimers. The coiled-coil fusion-based approach also increased mevalonate production in Saccharomyces cerevisiae , thus demonstrating the wider applicability of this strategy.


2012 ◽  
Vol 23 (19) ◽  
pp. 3911-3922 ◽  
Author(s):  
Yongqiang Wang ◽  
Xinlei Zhang ◽  
Hong Zhang ◽  
Yi Lu ◽  
Haolong Huang ◽  
...  

The highly abundant α-helical coiled-coil motif not only mediates crucial protein–protein interactions in the cell but is also an attractive scaffold in synthetic biology and material science and a potential target for disease intervention. Therefore a systematic understanding of the coiled-coil interactions (CCIs) at the organismal level would help unravel the full spectrum of the biological function of this interaction motif and facilitate its application in therapeutics. We report the first identified genome-wide CCI network in Saccharomyces cerevisiae, which consists of 3495 pair-wise interactions among 598 predicted coiled-coil regions. Computational analysis revealed that the CCI network is specifically and functionally organized and extensively involved in the organization of cell machinery. We further show that CCIs play a critical role in the assembly of the kinetochore, and disruption of the CCI network leads to defects in kinetochore assembly and cell division. The CCI network identified in this study is a valuable resource for systematic characterization of coiled coils in the shaping and regulation of a host of cellular machineries and provides a basis for the utilization of coiled coils as domain-based probes for network perturbation and pharmacological applications.


2018 ◽  
Vol 74 (3) ◽  
pp. 194-204 ◽  
Author(s):  
Iracema Caballero ◽  
Massimo Sammito ◽  
Claudia Millán ◽  
Andrey Lebedev ◽  
Nicolas Soler ◽  
...  

ARCIMBOLDOsolves the phase problem by combining the location of small model fragments usingPhaserwith density modification and autotracing usingSHELXE. Mainly helical structures constitute favourable cases, which can be solved using polyalanine helical fragments as search models. Nevertheless, the solution of coiled-coil structures is often complicated by their anisotropic diffraction and apparent translational noncrystallographic symmetry. Long, straight helices have internal translational symmetry and their alignment in preferential directions gives rise to systematic overlap of Patterson vectors. This situation has to be differentiated from the translational symmetry relating different monomers.ARCIMBOLDO_LITEhas been run on single workstations on a test pool of 150 coiled-coil structures with 15–635 amino acids per asymmetric unit and with diffraction data resolutions of between 0.9 and 3.0 Å. The results have been used to identify and address specific issues when solving this class of structures usingARCIMBOLDO. Features fromPhaserv.2.7 onwards are essential to correct anisotropy and produce translation solutions that will pass the packing filters. As the resolution becomes worse than 2.3 Å, the helix direction may be reversed in the placed fragments. Differentiation between true solutions and pseudo-solutions, in which helix fragments were correctly positioned but in a reverse orientation, was found to be problematic at resolutions worse than 2.3 Å. Therefore, after every new fragment-placement round, complete or sparse combinations of helices in alternative directions are generated and evaluated. The final solution is once again probed by helix reversal, refinement and extension. To conclude, density modification andSHELXEautotracing incorporating helical constraints is also exploited to extend the resolution limit in the case of coiled coils and to enhance the identification of correct solutions. This study resulted in a specialized mode withinARCIMBOLDOfor the solution of coiled-coil structures, which overrides the resolution limit and can be invoked from the command line (keyword coiled_coil) orARCIMBOLDO_LITEtask interface inCCP4i.


2019 ◽  
Author(s):  
Susanna K. Elledge ◽  
Hai L. Tran ◽  
Alec H. Christian ◽  
Veronica Steri ◽  
Byron Hann ◽  
...  

AbstractChemical modification of antibodies is one of the most important bioconjugations utilized by biologists and biotechnology. To date, the field has been dominated by random modification of lysines or more site-specific labeling of cysteines, each with attendant challenges. Recently we have developed oxaziridine chemistry for highly selective and efficient sulfimide modification of methionine called redox-activated chemical tagging (ReACT). Here, we systematically scanned methionines throughout one of the most popular antibody scaffolds, trastuzumab, for antibody engineering and drug conjugation. We tested the expression, reactivities, and stabilities of 123 single engineered methionines distributed over the surface of the antibody when reacted with oxaziridine. We found uniformly high expression for these mutants and generally good reaction efficiencies with the panel of oxaziridines. Remarkably, the stability to hydrolysis of the sulfimide varied more than ten-fold depending on temperature and the site of the engineered methionine. Interestingly, the most stable and reactive sites were those that were partially buried, likely because of their reduced access to water. There was also a ten-fold variation in stability depending on the nature of the oxaziridine, which we determined was inversely correlated with the electrophilic nature of the sulfimide. Importantly, the stabilities of the best analogs and antibody drug conjugate potencies were comparable to those reported for cysteine-maleimide modifications of trastuzumab. We also found our antibody drug conjugates to be potent in a breast cancer mouse xenograft model. These studies provide a roadmap for broad application of ReACT for efficient, stable, and site-specific antibody and protein bioconjugation.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Marcus D Hartmann ◽  
Claudia T Mendler ◽  
Jens Bassler ◽  
Ioanna Karamichali ◽  
Oswin Ridderbusch ◽  
...  

Coiled coils are the best-understood protein fold, as their backbone structure can uniquely be described by parametric equations. This level of understanding has allowed their manipulation in unprecedented detail. They do not seem a likely source of surprises, yet we describe here the unexpected formation of a new type of fiber by the simple insertion of two or six residues into the underlying heptad repeat of a parallel, trimeric coiled coil. These insertions strain the supercoil to the breaking point, causing the local formation of short β-strands, which move the path of the chain by 120° around the trimer axis. The result is an α/β coiled coil, which retains only one backbone hydrogen bond per repeat unit from the parent coiled coil. Our results show that a substantially novel backbone structure is possible within the allowed regions of the Ramachandran space with only minor mutations to a known fold.


2007 ◽  
Vol 189 (16) ◽  
pp. 6048-6056 ◽  
Author(s):  
Rong Gao ◽  
David G. Lynn

ABSTRACT A coordinated response to a complex and dynamic environment requires an organism to simultaneously monitor and interpret multiple signaling cues. In bacteria and some eukaryotes, environmental responses depend on the histidine autokinases (HKs). For example, VirA, a large integral membrane HK from Agrobacterium tumefaciens, regulates the expression of virulence genes in response to signals from multiple molecular classes (phenol, pH, and sugar). The ability of this pathogen to perceive inputs from different known host signals within a single protein receptor provides an opportunity to understand the mechanisms of signal integration. Here we exploited the conserved domain organization of the HKs and engineered chimeric kinases to explore the signaling mechanisms of phenol sensing and pH/sugar integration. Our data implicate a piston-assisted rotation of coiled coils for integration of multiple inputs and regulation of critical responses during pathogenesis.


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