Figure 3.

(a) Structure of human tropoelastin with alternating hydrophobic and hydrophilic domains, adapted from [47], Copyright (2005), with permission from Elsevier. (b) Tropoelastin is secreted from the cell, (c) self-assembles into a coacervate form, whereupon it is (d) crosslinked and deposited onto a microfibrillar scaffold, forming a growing elastic fiber. (e) Tropoelastin structure based on small-angle X-ray scattering, adapted from [48] with permission from the National Academy of Science, USA. (f) Scanning electron micrograph of coacervates of tropoelastin, adapted from [49], Copyright (2011), with permission from Elsevier. (g) Scanning electron micrograph of elastic fiber purified from human skin biopsies, adapted from [50] with permission from John Wiley and Sons. (h) Elastic network model of a SAXS-based structure of tropoelastin. (i) Wild type (WT) tropoelastin global dynamics, depicting the twist of the N-terminal scissors-like flexion of the hinge and foot regions. (j) Representative solution shapes of wild type tropoelastin showing conformations consistent with the range of molecular motions defined by the elastic network model. (k) Domain motion of WT+22 tropoelastin, characterized by the N-terminal bend along the perpendicular axis of the body and the parallel motion between the hinge region and the foot region. (l) Change in representative angles for four models: WT, mutant tropoelastin (WT+22), WT with a stiffened hinge region representative of alpha helix–to–beta sheet transition (WT with stiff hinge), and WT with a softened hinge region as an alternate control (WT with soft hinge). Corresponding model representations are presented below. The color bar indicates relative stiffness in the structure. (h-l) are adapted from [51] licensed under CC BY-NC 4.0 from AAAS.