Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Cross-beta spine architecture of fibrils formed by the amyloidogenic segment NFGSVQFV of medin from solid-state NMR and X-ray fiber diffraction measurements
AU - Madine, Jillian
AU - Copland, Alastair
AU - Serpell, Louise C
AU - Middleton, David A
PY - 2009/4/14
Y1 - 2009/4/14
N2 - Over 30 polypeptides are known to assemble into highly ordered fibrils associated with pathological disorders known collectively as amyloidoses. Structural studies of short model peptides are beginning to reveal trends in the types of molecular interactions that drive aggregation and stabilize the packing of beta-sheet layers within fibrillar assemblies. This work investigates the molecular architecture of fibrils formed by the peptide AMed42-49 representing residues 42-49 of the 50 amino acid polypeptide medin associated with aortic medial amyloid, the most common form of senile localized amyloid. The peptide aggregates within 2 days to form bundles of microcrystalline-like needles displaying a high degree of order. Fibrils were prepared from peptides containing up to 23 13C labels, and the solid-state nuclear magnetic resonance (SSNMR) method rotational resonance (RR) was used to determine constraints on the distances between selective atomic sites within fibrils. The constraints are consistent with unbroken beta-strands hydrogen bonded in a parallel in-register arrangement within beta-sheets. Further RR measurements identify close (>6.5 A) contacts between residues F43 and V46 and between S45 and V46, which can only occur between beta-sheet layers and which are consistent with two principal models of beta-sheet arrangements. X-ray fiber diffraction from partially aligned fibrils revealed the classical amyloid diffraction pattern, and comparison of patterns calculated from model coordinates with experimental data allowed determination of a consistent molecular model.
AB - Over 30 polypeptides are known to assemble into highly ordered fibrils associated with pathological disorders known collectively as amyloidoses. Structural studies of short model peptides are beginning to reveal trends in the types of molecular interactions that drive aggregation and stabilize the packing of beta-sheet layers within fibrillar assemblies. This work investigates the molecular architecture of fibrils formed by the peptide AMed42-49 representing residues 42-49 of the 50 amino acid polypeptide medin associated with aortic medial amyloid, the most common form of senile localized amyloid. The peptide aggregates within 2 days to form bundles of microcrystalline-like needles displaying a high degree of order. Fibrils were prepared from peptides containing up to 23 13C labels, and the solid-state nuclear magnetic resonance (SSNMR) method rotational resonance (RR) was used to determine constraints on the distances between selective atomic sites within fibrils. The constraints are consistent with unbroken beta-strands hydrogen bonded in a parallel in-register arrangement within beta-sheets. Further RR measurements identify close (>6.5 A) contacts between residues F43 and V46 and between S45 and V46, which can only occur between beta-sheet layers and which are consistent with two principal models of beta-sheet arrangements. X-ray fiber diffraction from partially aligned fibrils revealed the classical amyloid diffraction pattern, and comparison of patterns calculated from model coordinates with experimental data allowed determination of a consistent molecular model.
KW - Amino Acid Sequence
KW - Amyloid
KW - Antigens, Surface
KW - Carbon Isotopes
KW - Hydrogen Bonding
KW - Magnetic Resonance Spectroscopy
KW - Milk Proteins
KW - Peptide Fragments
KW - Protein Conformation
KW - Protein Structure, Secondary
KW - X-Ray Diffraction
U2 - 10.1021/bi802164e
DO - 10.1021/bi802164e
M3 - Journal article
C2 - 19196164
VL - 48
SP - 3089
EP - 3099
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 14
ER -