bi201356v_si_001.pdf (2 MB)
Structural Characterization of the Caveolin Scaffolding Domain in Association with Cholesterol-Rich Membranes
journal contribution
posted on 2012-01-10, 00:00 authored by Cody L. Hoop, V. N. Sivanandam, Ravindra Kodali, Matthew N. Srnec, Patrick C. A. van der WelMembers of the caveolin protein family are implicated
in the formation
of caveolae and play important roles in a number of signaling pathways
and in the regulation of various proteins. We employ complementary
spectroscopic methods to study the structure of the caveolin scaffolding
domain (CSD) in caveolin-1 fragments, while bound to cholesterol-rich
membranes. This key domain is thought to be involved in multiple critical
functions that include protein recognition, oligomerization, and cholesterol
binding. In our membrane-bound peptides, residues within the flanking
intramembrane domain (IMD) are found to adopt an α-helical structure,
consistent with its commonly believed helical hairpin conformation.
Intriguingly, in these same peptides, we observe a β-stranded
conformation for residues in the CSD, contrasting with earlier reports,
which commonly do not reflect β-structure. Our experimental
data based on solid-state NMR, CD, and FTIR are found to be consistent
with computational analyses of the secondary structure preference
of the primary sequence. We discuss how our structural data of membrane
binding Cav fragments may match certain general features of cholesterol-binding
domains and could be consistent with the role for CSD in protein recognition
and homo-oligomerization.