autore: giovanni batignani
DESCRIPTION
Scopo della Tesi: DIRE INTRODUZIONE. Ultrafast dynamics in photoexcited Neuroglobin revealed by Femtosecond Stimulated Raman Scattering. Relatore: Tullio Scopigno. Autore: Giovanni Batignani. Emoproteine e Neuroglobina. - PowerPoint PPT PresentationTRANSCRIPT
Ultrafast dynamics in photoexcited Neuroglobin
revealedby Femtosecond Stimulated
Raman Scattering
Autore:Giovanni Batignani
Relatore:Tullio Scopigno
Emoproteine e Neuroglobina
Il nucleo di ogni emoproteina è costituito da uno ione di ferro,
che ne determina le funzionalità biologiche.
Heme
Ligando gassoso (O2, CO, NO)
Ferro
Amminoacidi
Funzione biologica ↔ formare e rompere legami
Specie deoxy pentacoordinata
Specie deoxy esacoordinata
Dinamica Ultraveloce
Tecnica Pump ProbeStudiare dinamiche di campioni fotoeccitati
∆t<1ps
Dinamica Ultraveloce
Time Resolved Resonance Raman (TR3)Citocromo cNeuroglobina deoxy
????
Fotolisi della Metionina
Stati transienti ??
δω≈10cm-1 δt=2ps
Jean-Louis Martin et al. 2007“…However, such studies are extremely challenging for the physiologically relevant ligand oxygen and have not been reported yet, even for the well studied oxygen carriers myoglobin and hemoglobin, presumably at least in part because of technical difficulties”
“…Because of the decreased spectral resolution in the subpicosecond Raman experiments, lines in these spectra are broader than in the steady-state spectra obtained with cw excitation.”
Dinamica Ultraveloce
Assorbimento Transiente (TA)
“Transient spectra indicate the formation of a 5-c domed species upon photoexcitation of the 6-c species, and thus photodissociation of an internal residue. The process appears similar to the way small ligands like CO can be photodissociated from ferrous heme-His-CO complexes. As, in contrast to small gaseous ligands, the internal ligands are restrained to heme proximity, full rebinding is observed on the picosecond time scale for all proteins.”
Femtosecond Stimulated Raman Scattering
Raman Pulse
Ram
an P
ulse
Raman Pulse
Timeline
Raman ProbeR
aman Probe
Raman spontaneo“transform limited”
δωδt>15ps·cm-1
…+𝒆
− 𝒊(𝝎
𝑹−𝝎
𝑷)𝒕
Phot
oche
mic
al P
ump
Ener
gy
“Reaction” coordinate
Actinic Pum
∆t
Risoluzione temporale illimitata
Timing cycle – 1 ms timebase:
WLC ON ON ON ON ….
RAMAN PULSE ON OFF ON OFF ….
PHOTOCHEM PUMP ON ON OFF OFF ….
Raman Pulse
Ram
an P
ump
WLG WL Probe
FSRS SetupFemtosecond Stimulated Raman Scattering
Femtosecond Stimulated Raman Scattering
Conclusioni
Risultati ottenuti
Conclusioni
Prospettive di ricerca future