Cryo-EM structure of cardiac amyloid fibrils from an immunoglobulin light chain (AL) amyloidosis patient

Swuec, Paolo; Lavatelli, Francesca; Tasaki, Masayoshi; Paissoni, Cristina; Rognoni, Paola; Maritan, Martina; Brambilla, Francesca; Milani, Paolo; Mauri, Pierluigi; Camilloni, Carlo; Palladini, Giovanni; Merlini, Giampaolo; Ricagno, Stéfano; Bolognesi, M.

doi:10.1101/444901

Cited by 22 publications

(88 citation statements)

References 24 publications

(34 reference statements)

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“…Their chemical shifts are typical for cysteines in the oxidized state. This finding is in agreement with an intact disulfide bond in both the two recent cryo-EM structures and the chemical shifts of 6aJL2_R25G fibrils (Lecoq et al 2019;Radamaker et al 2019;Swuec et al 2019).…”

Section: Assignment and Data Depositionsupporting

confidence: 89%

Solid state NMR assignments of a human λ-III immunoglobulin light chain amyloid fibril

et al. 2020

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The aggregation of antibody light chains is linked to systemic light chain (AL) amyloidosis, a disease where amyloid deposits frequently affect the heart and the kidney. We here investigate fibrils from the λ-III FOR005 light chain (LC), which is derived from an AL-patient with severe cardiac involvement. In FOR005, five residues are mutated with respect to its closest germline gene segment IGLV3-19 and IGLJ3. All mutations are located close to the complementarity determining regions (CDRs). The sequence segments responsible for the fibril formation are not yet known. We use fibrils extracted from the heart of this particular amyloidosis patient as seeds to prepare fibrils for solid-state NMR. We show that the seeds induce the formation of a specific fibril structure from the biochemically produced protein. We have assigned the fibril core region of the FOR005-derived fibrils and characterized the secondary structure propensity of the observed amino acids. As the primary structure of the aggregated patient protein is different for every AL patient, it is important to study, analyze and report a greater number of light chain sequences associated with AL amyloidosis.

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Section: Assignment and Data Depositionsupporting

confidence: 89%

Solid state NMR assignments of a human λ-III immunoglobulin light chain amyloid fibril

et al. 2020

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“…Using MAS solid-state NMR, we could identify the residues in FOR005 fibrils that form the rigid core of the fibril. is buried in the core (13). This is agreement with a study that suggests that mutations in the N-terminal β-strand accelerate fibril formation (30).…”

Section: Discussionsupporting

confidence: 91%

“…Nevertheless, clear spectral patterns can be recognized indicating that a fraction of the protein adopts a preferred conformation. The linewidth of 13 Figure 3A). K38 is sequentially assigned and observable in the 2D NCACX experiment (red contours in Figure 3A).…”

Section: Figure 2 Biophysical Characterization Of For005 V L Variantmentioning

confidence: 99%

Amyloidogenic core of a human λ-III immunoglobulin light chain fibril and their germline variants probed by MAS solid state NMR

Pradhan

Annamalai

Sarkar

et al. 2020

Preprint

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Systemic antibody light chains (AL) amyloidosis is characterized by deposition of amyloid fibrils derived from a particular antibody light chain. Cardiac involvement is a major risk factor for mortality. Using MAS solid-state NMR, we study the fibril structure of a recombinant light chain fragment corresponding to the fibril protein from patient FOR005, together with fibrils formed by protein sequence variants that reflect the closest germline (GL) sequence. Both analyzed fibril structures were seeded with ex-vivo amyloid fibrils purified from the explanted heart of this patient. We find that residues 11-42 and 69-102 adopt β-sheet conformation in patient protein fibrils. We identify glycine-49 that is mutated with respect to the germline sequence into arginine-49 as a key residue that forms a salt bridge to aspartate-25 in the patient protein fibril structure. Fibrils from the GL protein and from the patient protein harboring the single point mutation R49G can be both heterologously seeded using patient ex-vivo fibrils. Seeded R49G fibrils show an increased heterogeneity for the C-terminal residues 80-102 which is reflected by the disappearance of all resonances of these residues. By contrast, residues 11-42 and 69-77, which are visible in the MAS solid-state NMR spectra show 13Cα chemical shifts that are highly similar to patient fibrils. The mutation R49G thus induces a conformational heterogeneity at the C-terminus in the fibril state, while the overall fibril topology is retained.

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“…For a sequence alignment of the different light chains studied by NMR spectroscopy see Figure S11. A cryo‐EM structure of a light‐chain aggregate extracted ex vivo and showing a similar sequence (differing in 12 positions) to that studied here has been posted recently on bioRxiv . It, however, displays a different architecture, as can be judged when comparing it to the secondary structure elements presented here.…”

Section: Figurementioning

confidence: 60%

A Substantial Structural Conversion of the Native Monomer Leads to in‐Register Parallel Amyloid Fibril Formation in Light‐Chain Amyloidosis

et al. 2019

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Amyloid light‐chain (AL) amyloidosis is a rare disease in which plasma‐cell‐produced monoclonal immunoglobulin light chains misfold and become deposited as fibrils in the extracellular matrix. λ6 subgroup light chains are particularly fibrillogenic, and around 25 % of amyloid‐associated λ6 light chains exist as the allotypic G24R variant that renders the protein less stable. The molecular details of this process, as well as the structures of the fibrils, are unknown. We have used solid‐state NMR to investigate different fibril polymorphs. The secondary structures derived from NMR predominantly show β‐strands, including in former turn or helical regions, and provide a molecular basis for previously identified fibrillogenic hotspots. We have determined, by using differentially 15N:13C‐labeled samples, that the β‐strands are stacked in‐register parallel in the fibrils. This supramolecular arrangement shows that the native globular folds rearrange substantially upon fibrillization, and rules out the previously hypothesized fibril formation from native monomers.

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Cryo-EM structure of cardiac amyloid fibrils from an immunoglobulin light chain (AL) amyloidosis patient

Cited by 22 publications

References 24 publications

Solid state NMR assignments of a human λ-III immunoglobulin light chain amyloid fibril

Solid state NMR assignments of a human λ-III immunoglobulin light chain amyloid fibril

Amyloidogenic core of a human λ-III immunoglobulin light chain fibril and their germline variants probed by MAS solid state NMR

A Substantial Structural Conversion of the Native Monomer Leads to in‐Register Parallel Amyloid Fibril Formation in Light‐Chain Amyloidosis

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