Site-Directed Spin Labeling

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Site-Directed Spin Labeling
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Spin Label SolventAccessibility
130
133
131

• Deduced from measurement of the collision
  frequency with small paramagnetic molecules such
  as NiEDDA and Oxygen.
• Reagents are differentially soluble ? assignment
  of the topographical location.
• Quantitative measurement ? high resolution
  structural assignment.

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Accessibility Pattern of Anisotropically Solvated
Transmembrane Helix
O2 Gradient in the Bilayer
NiEDDA Concentration in the Bilayer
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Accessibilities of Spin label Side Chains Along
Selected Segments of Apo-MsbA
TM 2
TM 5
TM 6
ICD
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Dissection of a Fold
Supersecondary structure
Secondary Structure and Solvent Accessibility
..Y I S R E F H R R Y R L P .. ..c b c b c b e b
e b e b e .. b -Strand
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Distance Determination in Proteins
80R1
29 Å
10-60 Å
38 Å
47 Å
65R1
130R1
Pair Ca- Ca R1-R1 65/80 23 Å 28
Å 80/135 27 Å 37 Å 65/135 34 Å
46 Å
Borbat, P.P., Mchaourab, H.S., and Freed, J.H.
(2002). Journal of the American Chemical
Society. 124, 5304-5314.
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Packing of Helices D and G
C?-C? R1-R1
86/122
X 20
8 Å
lt10 Å
86/119
X 20
10 Å
lt10 Å
86/115
X 10
13 Å
14 Å
Sum of Singles
Doubles
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Long Range Distance Measurements in T4 Lysozyme
by Double-Quantum ESR
80R1
29 Å
Pair Ca- Ca R1-R1 65/80 23 ?
28 ? 80/135 27 ? 37 ? 65/135
34 ? 46 ?
38 Å
47 Å
65R1
130R1
Borbat, P.P., Mchaourab, H.S., and Freed, J.H.
(2002). Journal of the American Chemical
Society. 124, 5304-5314.
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