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Transglutaminase-mediated cross-linking of tropoelastin to fibrillin stabilises the elastin precursor prior to elastic fibre assembly

DOI: 10.1016/j.jmb.2020.08.023 DOI Help

Authors: Michael P. Lockhart-Cairns (University of Manchester) , Helena Newandee (University of Connecticut) , Jennifer Thomson (Wellcome Centre for Cell-Matrix Research) , Anthony S. Weiss (The University of Sydney) , Clair Baldock (University of Manchester) , Anna Tarakanova (University of Connecticut)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Molecular Biology

State: Published (Approved)
Published: September 2020
Diamond Proposal Number(s): 17773

Abstract: Elastic fibres are essential components of all mammalian elastic tissues such as blood vessels, lung and skin, and are critically important for the mechanical properties they endow. The main components of elastic fibres are elastin and fibrillin, where correct formation of elastic fibres requires a fibrillin microfibril scaffold for the deposition of elastin. It has been demonstrated previously that the interaction between fibrillin and tropoelastin, the elastin precursor, increases the rate of assembly of tropoelastin. Furthermore, tropoelastin and fibrillin can be cross-linked by transglutaminase-2 but the function of cross-linking on their elastic properties is yet to be elucidated. Here we show that transglutaminase cross-linking supports formation of a 1:1 stoichiometric fibrillin-tropoelastin complex. SAXS data show that the complex retains features of the individual proteins, but is elongated supporting end-to-end assembly. Elastic network models were constructed to compare the dynamics of tropoelastin and fibrillin individually as well as in the cross-linked complex. Normal mode analysis was performed to determine the structures' most energetically favourable, biologically accessible motions which show that within the complex, tropoelastin is less mobile and this molecular stabilisation extends along the length of the tropoelastin molecule to regions remote from the cross-linking site. Together, these data suggest a long-range stabilising effect of cross-linking that occurs due to the covalent linkage of fibrillin to tropoelastin. This work provides insight into the interactions of tropoelastin and fibrillin and how cross-link formation stabilises the elastin precursor so it is primed for elastic fibre assembly.

Journal Keywords: Tropoelastin; Elastin; Fibrillin; Tissue transglutaminase; Elastic fibres; Coacervation

Subject Areas: Biology and Bio-materials

Instruments: B21-High Throughput SAXS

Discipline Tags:

Life Sciences & Biotech Structural biology

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)