Leiden University Student Repository

Vries, Anna de (2020)

EPR for flexible proteins - Spin labelling cp-2 with IAP

Bachelor thesis | Natuurkunde (BSc)

Deposit of amyloid fibrils as Amyloid beta (Aβ) is expected to be involved in neurodegenerative diseases. Cyclic D,L-α-peptide (cp-2) is found to interact with Aβ, reducing its toxicity1,2. The peptide cp-2 is interesting to study as it could play a role in treating neurodegenerative diseases. The anti-amyloidogenic properties of cp-2 and the interactions of cp-2 with Aβ can be studied with continuous wave (cw) Electron paramagnetic resonance (EPR). For the cwEPR study, a spin label needs to be attached to cp-2. Here we discuss the results we obtained of spin labelling cp-2 with 3-(2-iodoacetamide)-proxyl (IAP). After the reaction of cp-2 with IAP we use analytical Liquid chromatography – mass spectrometry (LCMS) to identify and separate the different components in the reaction solution and preparative High performance liquid chromatography (HPLC) to isolate the labelled peptide from the solution. In this report we show that cp-2 undergoes structural changes when labelled with IAP....Show moreDeposit of amyloid fibrils as Amyloid beta (Aβ) is expected to be involved in neurodegenerative diseases. Cyclic D,L-α-peptide (cp-2) is found to interact with Aβ, reducing its toxicity1,2. The peptide cp-2 is interesting to study as it could play a role in treating neurodegenerative diseases. The anti-amyloidogenic properties of cp-2 and the interactions of cp-2 with Aβ can be studied with continuous wave (cw) Electron paramagnetic resonance (EPR). For the cwEPR study, a spin label needs to be attached to cp-2. Here we discuss the results we obtained of spin labelling cp-2 with 3-(2-iodoacetamide)-proxyl (IAP). After the reaction of cp-2 with IAP we use analytical Liquid chromatography – mass spectrometry (LCMS) to identify and separate the different components in the reaction solution and preparative High performance liquid chromatography (HPLC) to isolate the labelled peptide from the solution. In this report we show that cp-2 undergoes structural changes when labelled with IAP. We found suggestions of the presence of the linear variant of cp-2 and linear labelled cp-2. However we also obtained the desiderated labelled cp-2, suggesting that this method can be used to spin label cp-2 with IAP.Show less

EPR

cp-2

spin label

amyloid beta

Author

Vries, Anna de

Faculty

Faculty of Science

Supervisors

Huber, Martina

ECTS Credits

3

Language

en