Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains

Villalba, Miryam Ivette; Canul-Tec, Juan Carlos; Luna-Martínez, Oscar D.; Sánchez-Alcalá, Rosalba; Olamendi-Portugal, Timoteo; Rudino‐Pinera, E.; Rojas, Sonia Zhadira Celi; Sánchez‐López, Rosana; Fernández‐Velasco, D. Alejandro; Becerril, Baltazar

doi:10.1074/jbc.m114.629550

Cited by 13 publications

(11 citation statements)

References 55 publications

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“…To date, most studies dealing with the biophysical and structural properties of amyloidogenic LCs have focused specifically on V L domains, as they are abundant in fibrils: typically, V L domains belonging to amyloidogenic LCs are thermodynamically and kinetically unstable, while the three-dimensional structures of amyloidogenic and non-amyloidogenic V L studied match closely 11 – 15 . However, many observations stress the relevance of studying full length LCs: (i) although V L are abundant in fibrils, the full length LCs and C L domains have also been found in deposits 12 , 16 – 18 ; (ii) so far, FL LCs and not truncated forms, have been found soluble in blood and serum 19 ; iii) recent reports underline the relevance of the C L domain in determining both the biophysical properties and the aggregation propensity of LCs 20 – 23 .…”

Section: Introductionmentioning

confidence: 99%

Concurrent structural and biophysical traits link with immunoglobulin light chains amyloid propensity

Oberti

Rognoni

Barbiroli

et al. 2017

Sci Rep

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Light chain amyloidosis (AL), the most common systemic amyloidosis, is caused by the overproduction and the aggregation of monoclonal immunoglobulin light chains (LC) in target organs. Due to genetic rearrangement and somatic hypermutation, virtually, each AL patient presents a different amyloidogenic LC. Because of such complexity, the fine molecular determinants of LC aggregation propensity and proteotoxicity are, to date, unclear; significantly, their decoding requires investigating large sets of cases. Aiming to achieve generalizable observations, we systematically characterised a pool of thirteen sequence-diverse full length LCs. Eight amyloidogenic LCs were selected as responsible for severe cardiac symptoms in patients; five non-amyloidogenic LCs were isolated from patients affected by multiple myeloma. Our comprehensive approach (consisting of spectroscopic techniques, limited proteolysis, and X-ray crystallography) shows that low fold stability and high protein dynamics correlate with amyloidogenic LCs, while hydrophobicity, structural rearrangements and nature of the LC dimeric association interface (as observed in seven crystal structures here presented) do not appear to play a significant role in defining amyloid propensity. Based on the structural and biophysical data, our results highlight shared properties driving LC amyloid propensity, and these data will be instrumental for the design of synthetic inhibitors of LC aggregation.

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Section: Introductionmentioning

confidence: 99%

Concurrent structural and biophysical traits link with immunoglobulin light chains amyloid propensity

Oberti

Rognoni

Barbiroli

et al. 2017

Sci Rep

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“…In general, healthy individuals have a kappa to lambda ratio of two to one while AL patients have a kappa to lambda ratio of one to three [3], with a majority of the lambda light chains coming from only a few possible germ lines, such as 3r and/or 6a [8]. Particularly, a mutation of Arg to Gly in position 24 for germ-line 6a has been found in 25% of AL patient samples.…”

Section: Introductionmentioning

confidence: 99%

Different Dynamics in 6aJL2 Proteins Associated with AL Amyloidosis, a Conformational Disease

Maya-Martinez

French-Pacheco

Valdés-García

et al. 2019

IJMS

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Light-chain amyloidosis (AL) is the most common systemic amyloidosis and is caused by the deposition of mainly insoluble immunoglobulin light chain amyloid fibrils in multiple organs, causing organ failure and eventually death. The germ-line λ6a has been implicated in AL, where a single point mutant at amino acid 24 (6aJL2-R24G) has been observed in around 25% of patient samples. Structural analysis has shown only subtle differences between both proteins; nevertheless, 6aJL2-R24G is more prone to form amyloid fibrils. To improve our understanding of the role of protein flexibility in amyloid fibril formation, we have used a combination of solution nuclear magnetic resonance spectroscopy and molecular dynamics simulations to complement the structural insight with dynamic knowledge. Fast timescale dynamics (ps–ns) were equivalent for both proteins, but suggested exchange events for some residues. Even though most of the intermediate dynamics (μs–ms) occurred at a similar region for both proteins, the specific characteristics are very different. A minor population detected in the dispersion experiments could be associated with the formation of an off-pathway intermediate that protects from fiber formation more efficiently in the germ-line protein. Moreover, we found that the hydrogen bond patterns for both proteins are similar, but the lifetime for the mutant is significantly reduced; as a consequence, there is a decrease in the stability of the tertiary structure that extends throughout the protein and leads to an increase in the propensity to form amyloid fibers.

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“…Although germ lines can be identified as kappa (j) or lambda (k) with expression levels in humans of 60% and 40%, respectively [9], it is striking that k V L s encoded by germ lines 6a and 3r are highly susceptible to amyloid aggregation [10]. In order to elucidate the propensity of k6a to amyloid aggregation, a recombinant model light chain encoded by germ line 6a and JL2 gene segments and denominated 6aJL2 was constructed [11,12]. In vitro experiments revealed that the protein product, 6aJL2, showed a thermodynamic stability of 5.2 kcalÁmol À1 , higher than that of other amyloidogenic V L s derived from this germ line.…”

Section: Introductionmentioning

confidence: 99%

Stabilizing an amyloidogenic λ6 light chain variable domain

et al. 2017

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Site-directed Mutagenesis Reveals Regions Implicated in the Stability and Fiber Formation of Human λ3r Light Chains

Cited by 13 publications

References 55 publications

Concurrent structural and biophysical traits link with immunoglobulin light chains amyloid propensity

Concurrent structural and biophysical traits link with immunoglobulin light chains amyloid propensity

Different Dynamics in 6aJL2 Proteins Associated with AL Amyloidosis, a Conformational Disease

Stabilizing an amyloidogenic λ6 light chain variable domain

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