The solution structures of native and patient monomeric human IgA1 reveal asymmetric extended structures: implications for function and IgAN disease

Hui, Gar Kay; Wright, David W.; Vennard, Owen L.; Rayner, Lucy E.; Pang, Melisa; Yeo, See Cheng; Gor, Jayesh; Molyneux, Karen; Barratt, Jonathan; Perkins, Stephen J.

doi:10.1042/bj20150612

Cited by 23 publications

(23 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our current (and third) strategy in SASSIE started from an energy-minimized structure, used rapid Monte Carlo sampling methods on a high-performance computing platform, rejected structures with poor stereochemistry at the point of generation, and employed an integrated modeling workflow for scattering fits (22). In this way, human IgG2 antibody was modeled from SANS data, and human IgA1 antibody likewise from SAXS and SANS data sets (13,65). This third approach will enable more ambitious modeling of antibody solution structures in the future, whether this will be to determine new types of structures or to monitor conformational changes.…”

Section: Discussionmentioning

confidence: 99%

“…This modeling procedure raises the issue of how to interpret the resulting conformations. Previously, principal component analyses were used to identify four distinct clusters of structures that defined the asymmetric solution structure of human IgA1 (65). Here, the alternative representation of the fitted solution structures based on plots of abs(d2 À d3) vs. d1 resulted in two different conformations, termed Clusters a and b, that gave indistinguishable scattering fits.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Atomistic Modeling of Scattering Curves for Human IgG1/4 Reveals New Structure-Function Insights

Wright

Elliston

Hui

et al. 2019

Biophysical Journal

View full text Add to dashboard Cite

Small angle x-ray and neutron scattering are techniques that give solution structures for large macromolecules. The creation of physically realistic atomistic models from known high-resolution structures to determine joint x-ray and neutron scattering best-fit structures offers a, to our knowledge, new method that significantly enhances the utility of scattering. To validate this approach, we determined scattering curves for two human antibody subclasses, immunoglobulin G (IgG) 1 and IgG4, on five different x-ray and neutron instruments to show that these were reproducible, then we modeled these by Monte Carlo simulations. The two antibodies have different hinge lengths that connect their antigen-binding Fab and effector-binding Fc regions. Starting from 231,492 and 190,437 acceptable conformations for IgG1 and IgG4, respectively, joint x-ray and neutron scattering curve fits gave low goodness-of-fit R factors for 28 IgG1 and 2748 IgG4 structures that satisfied the disulphide connectivity in their hinges. These joint best-fit structures showed that the best-fit IgG1 models had a greater separation between the centers of their Fab regions than those for IgG4, in agreement with their hinge lengths of 15 and 12 residues, respectively. The resulting asymmetric IgG1 solution structures resembled its crystal structure. Both symmetric and asymmetric solution structures were determined for IgG4. Docking simulations with our best-fit IgG4 structures showed greater steric clashes with its receptor to explain its weaker FcgRI receptor binding compared to our best-fit IgG1 structures with fewer clashes and stronger receptor binding. Compared to earlier approaches for fitting molecular antibody structures by solution scattering, we conclude that this joint fit approach based on x-ray and neutron scattering data, combined with Monte Carlo simulations, significantly improved our understanding of antibody solution structures. The atomistic nature of the output extended our understanding of known functional differences in Fc receptor binding between IgG1 and IgG4.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Atomistic Modeling of Scattering Curves for Human IgG1/4 Reveals New Structure-Function Insights

Wright

Elliston

Hui

et al. 2019

Biophysical Journal

View full text Add to dashboard Cite

show abstract

“…Thus, in order to probe the conformation of entire IgA monomers rather than the separate Fab and Fc regions, lower resolution techniques, including electron microscopy (EM), and more recently, X-ray and neutron scattering of IgA in solution, have been used. These have been useful in predicting the overall dimensions of IgA molecules, and have led to an understanding that the IgA1 has a greater average Fab centre to Fab centre distance than IgA2: 16.9 nm for IgA1 compared with just 8.2 nm for IgA2 [21][22][23][24][25][26].…”

Section: Structure Of Monomeric Igamentioning

confidence: 99%

IgA: Structure, Function, and Developability

2019

View full text Add to dashboard Cite

Immunoglobulin A (IgA) plays a key role in defending mucosal surfaces against attack by infectious microorganisms. Such sites present a major site of susceptibility due to their vast surface area and their constant exposure to ingested and inhaled material. The importance of IgA to effective immune defence is signalled by the fact that more IgA is produced than all the other immunoglobulin classes combined. Indeed, IgA is not just the most prevalent antibody class at mucosal sites, but is also present at significant concentrations in serum. The unique structural features of the IgA heavy chain allow IgA to polymerise, resulting in mainly dimeric forms, along with some higher polymers, in secretions. Both serum IgA, which is principally monomeric, and secretory forms of IgA are capable of neutralising and removing pathogens through a range of mechanisms, including triggering the IgA Fc receptor known as FcαRI or CD89 on phagocytes. The effectiveness of these elimination processes is highlighted by the fact that various pathogens have evolved mechanisms to thwart such IgA-mediated clearance. As the structure–function relationships governing the varied capabilities of this immunoglobulin class come into increasingly clear focus, and means to circumvent any inherent limitations are developed, IgA-based monoclonal antibodies are set to emerge as new and potent options in the therapeutic arena.

show abstract

“…SasCalc (golden vector method) [35] allows the computation of neutron scattering profiles from structures and it can be freely accessed from a website [36]. Examples of this methodology are published in the literature [29], [34], [37], [38], [39], [40]. In the absence of crystallographic data, there are tools to generate molecular shapes that fit the experimental data, such as DAMMIF [41].…”

Section: Overview Of Small-angle Neutron Scatteringmentioning

confidence: 99%

Investigating Structure and Dynamics of Proteins in Amorphous Phases Using Neutron Scattering

Castellanos

McAuley

Curtis

2017

Computational and Structural Biotechnology Journal

View full text Add to dashboard Cite

In order to increase shelf life and minimize aggregation during storage, many biotherapeutic drugs are formulated and stored as either frozen solutions or lyophilized powders. However, characterizing amorphous solids can be challenging with the commonly available set of biophysical measurements used for proteins in liquid solutions. Therefore, some questions remain regarding the structure of the active pharmaceutical ingredient during freezing and drying of the drug product and the molecular role of excipients. Neutron scattering is a powerful technique to study structure and dynamics of a variety of systems in both solid and liquid phases. Moreover, neutron scattering experiments can generally be correlated with theory and molecular simulations to analyze experimental data. In this article, we focus on the use of neutron techniques to address problems of biotechnological interest. We describe the use of small-angle neutron scattering to study the solution structure of biological molecules and the packing arrangement in amorphous phases, that is, frozen glasses and freeze-dried protein powders. In addition, we discuss the use of neutron spectroscopy to measure the dynamics of glassy systems at different time and length scales. Overall, we expect that the present article will guide and prompt the use of neutron scattering to provide unique insights on many of the outstanding questions in biotechnology.

show abstract

The solution structures of native and patient monomeric human IgA1 reveal asymmetric extended structures: implications for function and IgAN disease

Cited by 23 publications

References 70 publications

Atomistic Modeling of Scattering Curves for Human IgG1/4 Reveals New Structure-Function Insights

Atomistic Modeling of Scattering Curves for Human IgG1/4 Reveals New Structure-Function Insights

IgA: Structure, Function, and Developability

Investigating Structure and Dynamics of Proteins in Amorphous Phases Using Neutron Scattering

Contact Info

Product

Resources

About