Regensburg 2004 – scientific programme

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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology

SYLS 3: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"

SYLS 3.55: Poster

Wednesday, March 10, 2004, 16:00–18:30, B

Polarised proton spin domains in catalase from bovine liver — •Heinrich Stuhrmann^1,2, B. van den Brandt³, J. Gaillard⁴, H. Glättli⁵, I. Grillo⁶, H. Jouve¹, R. Kahn¹, J. Kohlbrecher³, J.A. Konter³, E. Leymarie⁵, S. Mango³, R.P. May⁶, O. Zimmer⁷, and P. Hautle³ — ¹Institut de Biologie Structurale Jean Pierre Ebel, F-38027 Grenoble cedex 1, France — ²GKSS Forschungszentrum, D-21502 Geesthacht, Germany — ³Paul Scherrer Institute, CH-5232 Villingen PSI, Switzerland — ⁴Commissariat à l’Energie Antomique, CEA Grenoble, CEA/DSM/DRFMC/SCIB, F-38054 Grenoble, France — ⁵Commissariat à l’Energie Atomique, CE Saclay/DSM/DRECAM/SPEC and LLB, F-91191 Gif-sur Yvette cedex, France — ⁶Institut Laue Langevin, BP 156, F-38042 Grenoble cedex 1, France — ⁷Physics Department E18, Technische Universität München, D-85748 Garching, Germany

In very dilute paramagnets selective dynamic nuclear polarisation of proton spins close to paramagnetic centres provides an amplitude of polarised neutron scattering which is considerably stronger than that of magnetic neutron scattering. This is shown for bovine liver catalase, which is a homotetramer of 506 amino acids (MW=230 kD) with tyrosin-369 and possibly other tyrosins in a radical state. From comparison of time-resolved polarised neutron small-angle scattering with simultaneous NMR measurements it appears that at the onset of dynamic nuclear polarisation a large majority of the polarised protons are close to the unpaired electron of the tyrosyl radicals. Polarised proton spin domains are built up in less than 10 s, while the polarisation of the bulk proton remains low. Comparison of the time-resolved neutron scattering data with model calculations confirms the existence of tyrosyl-369