Molecular-level characterization of elastin-like constructs and human aortic elastin

TY - JOUR

T1 - Molecular-level characterization of elastin-like constructs and human aortic elastin

AU - Heinz, Andrea

AU - Schräder, Christoph U

AU - Baud, Stéphanie

AU - Keeley, Fred W

AU - Mithieux, Suzanne M

AU - Weiss, Anthony S

AU - Neubert, Reinhard H H

AU - Schmelzer, Christian E H

N1 - Copyright © 2014. Published by Elsevier B.V.

PY - 2014/9/1

Y1 - 2014/9/1

N2 - This study aimed to characterize the structures of two elastin-like constructs, one composed of a cross-linked elastin-like polypeptide and the other one of cross-linked tropoelastin, and native aortic elastin. The structures of the insoluble materials and human aortic elastin were investigated using scanning electron microscopy. Additionally, all samples were digested with enzymes of different specificities, and the resultant peptide mixtures were characterized by ESI mass spectrometry and MALDI mass spectrometry. The MS(2) data was used to sequence linear peptides, and cross-linked species were analyzed with the recently developed software PolyLinX. This enabled the identification of two intramolecularly cross-linked peptides containing allysine aldols in the two constructs. The presence of the tetrafunctional cross-link desmosine was shown for all analyzed materials and its quantification revealed that the cross-linking degree of the two in vitro cross-linked materials was significantly lower than that of native elastin. Molecular dynamics simulations were performed, based on molecular species identified in the samples, to follow the formation of elastin cross-links. The results provide evidence for the significance of the GVGTP hinge region of domain 23 for the formation of elastin cross-links. Overall, this work provides important insight into structural similarities and differences between elastin-like constructs and native elastin. Furthermore, it represents a step toward the elucidation of the complex cross-linking pattern of mature elastin.

AB - This study aimed to characterize the structures of two elastin-like constructs, one composed of a cross-linked elastin-like polypeptide and the other one of cross-linked tropoelastin, and native aortic elastin. The structures of the insoluble materials and human aortic elastin were investigated using scanning electron microscopy. Additionally, all samples were digested with enzymes of different specificities, and the resultant peptide mixtures were characterized by ESI mass spectrometry and MALDI mass spectrometry. The MS(2) data was used to sequence linear peptides, and cross-linked species were analyzed with the recently developed software PolyLinX. This enabled the identification of two intramolecularly cross-linked peptides containing allysine aldols in the two constructs. The presence of the tetrafunctional cross-link desmosine was shown for all analyzed materials and its quantification revealed that the cross-linking degree of the two in vitro cross-linked materials was significantly lower than that of native elastin. Molecular dynamics simulations were performed, based on molecular species identified in the samples, to follow the formation of elastin cross-links. The results provide evidence for the significance of the GVGTP hinge region of domain 23 for the formation of elastin cross-links. Overall, this work provides important insight into structural similarities and differences between elastin-like constructs and native elastin. Furthermore, it represents a step toward the elucidation of the complex cross-linking pattern of mature elastin.

KW - Amino Acid Sequence

KW - Aorta

KW - Cross-Linking Reagents

KW - Elastin

KW - Humans

KW - Microscopy, Electron, Scanning

KW - Models, Molecular

KW - Molecular Conformation

KW - Molecular Dynamics Simulation

KW - Molecular Sequence Data

KW - Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1016/j.matbio.2014.07.006

DO - 10.1016/j.matbio.2014.07.006

M3 - Journal article

C2 - 25068896

SN - 0945-053X

VL - 38

SP - 12

EP - 21

JO - Matrix Biology

JF - Matrix Biology

ER -