Molecular dynamics simulations on human fibulin-4 mutants D203A and E126K reveal conformational changes in EGF domains potentially responsible for enhanced protease lability and impaired extracellular matrix assembly

Sasaki T, von der Mark K, Lanig H (2019)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2019

Journal

Biochimica Et Biophysica Acta-Proteins and Proteomics Elsevier

Book Volume: 1867

Pages Range: 748-756

Journal Issue: 9

URI: https://www.sciencedirect.com/science/article/pii/S1570963919300871

DOI: 10.1016/j.bbapap.2019.05.007

Abstract

Fibulin-4 is a 50 kDa glycoprotein of elastic fibers and plays an important role in development and function of elastic tissues. Fibulin-4 consists of a tandem array of five calcium-binding epidermal growth factor-like modules flanked by N- and C-terminal domains. Mutations in the human fibulin-4 gene EFEMP2 have been identified in patients affected with various arteriopathies including aneurysm, arterial tortuosity, or stenosis, but the molecular basis of most genotype-phenotype correlations is unknown. Here we present biochemical and computer modelling approaches designed to gain further insight into changes in structure and function of two fibulin-4 mutations (E126K and D203A), which are potentially involved in Ca²⁺ binding in the EGF2 and EGF4 domain, respectively. Using recombinantly produced fibulin-4 mutant and wild type proteins we show that both mutations introduced additional protease cleavage sites, impaired extracellular assembly into fibers, and affected binding to to fibrillin-1, latent TGF-β-binding proteins, and the lysyl oxidase LOXL2. Molecular dynamics studies indicated that the E126K and D203A mutations do not necessarily result in a direct loss of the complexed Ca²⁺ ion after 500 ns simulation time, but in significantly enhanced fluctuations within the connecting loop between EGF3 and EGF4 domains and other conformational changes. In contrast, intentionally removing Ca²⁺ from EGF4 (D203A ΔCa) predicted dramatic changes in the protein structure. These results may explain the changes in protease cleavage sites, reduced secretion and impaired extracellular assembly of the E126K and D203A fibulin-4 mutants and provide further insight into understanding the molecular basis of the associated clinical phenotypes.

Authors with CRIS profile

Takako Sasaki Lehrstuhl für Experimentelle Medizin mit dem Schwerpunkt Molekulare Pathogeneseforschung Klaus von der Mark Medizinische Fakultät Harald Lanig Zentralinstitut für Scientific Computing (ZISC)

Additional Organisation(s)

Zentralinstitut für Scientific Computing (ZISC)

How to cite

APA:

Sasaki, T., von der Mark, K., & Lanig, H. (2019). Molecular dynamics simulations on human fibulin-4 mutants D203A and E126K reveal conformational changes in EGF domains potentially responsible for enhanced protease lability and impaired extracellular matrix assembly. Biochimica Et Biophysica Acta-Proteins and Proteomics, 1867(9), 748-756. https://dx.doi.org/10.1016/j.bbapap.2019.05.007

MLA:

Sasaki, Takako, Klaus von der Mark, and Harald Lanig. "Molecular dynamics simulations on human fibulin-4 mutants D203A and E126K reveal conformational changes in EGF domains potentially responsible for enhanced protease lability and impaired extracellular matrix assembly." Biochimica Et Biophysica Acta-Proteins and Proteomics 1867.9 (2019): 748-756.

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