User:Marc-Michael Blum/Sandbox1
From Proteopedia
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== Early history of the squid DFPase == | == Early history of the squid DFPase == | ||
<applet scene='User:Marc-Michael_Blum/Sandbox1/2gvw_rainbow/2' size='300' frame='true' align='right' caption='Tertiary structure of DFPase with the two calcium ions shown as green spheres' /> | <applet scene='User:Marc-Michael_Blum/Sandbox1/2gvw_rainbow/2' size='300' frame='true' align='right' caption='Tertiary structure of DFPase with the two calcium ions shown as green spheres' /> | ||
| - | WThe history of DFPase is closely linked to the pioneering work of David Nachmannsohn. Nachmannsohn worked on the theory of axonal conduction including the role of the cholinergic synaptic transmission system. Electrophysiology was still limited in the 1950s and 60s, with the modern patch clamp technique not available. To investigate axonal conduction with the available electrodes it was necessary to work with a model species that contained an axon large enough for electrode insertion. Nachmannsohn's group used the calmar Loligo pealei for their experiments and one of these experiments tried to block axonal conduction b irreversibly inhibiting the cholinesterases using the potent inhibitor diisopropyl fluorophosphate (DFP). The DFP concentration required to block conduction turned out to be | + | WThe history of DFPase is closely linked to the pioneering work of David Nachmannsohn. Nachmannsohn worked on the theory of axonal conduction including the role of the cholinergic synaptic transmission system. Electrophysiology was still limited in the 1950s and 60s, with the modern patch clamp technique not available. To investigate axonal conduction with the available electrodes it was necessary to work with a model species that contained an axon large enough for electrode insertion. Nachmannsohn's group used the calmar Loligo pealei for their experiments and one of these experiments tried to block axonal conduction b irreversibly inhibiting the cholinesterases using the potent inhibitor diisopropyl fluorophosphate (DFP). The DFP concentration required to block conduction in the axon turned out to be three orders of magnitude higher than the concentration required to inhibit cholinesterases in solution. |
| - | + | Francis C.G. Hoskin, at that time assistant professor at Columbia University NY, tried to investigate this surprising behavior by using 14C labeled DFP. He was able to show that radioactivity rapidly accumulated in the interior of the axon. But the compound found was not DFP but diisopropyl phosphoric acid. He concluded that the axonal envelope contains a potent enzyme that accounts for the high concentrations of DFP required to block conduction<ref>PMID:5225521</ref>. | |
==3D Structures of squid DFPase == | ==3D Structures of squid DFPase == | ||
Revision as of 13:17, 21 April 2010
Early history of the squid DFPase
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WThe history of DFPase is closely linked to the pioneering work of David Nachmannsohn. Nachmannsohn worked on the theory of axonal conduction including the role of the cholinergic synaptic transmission system. Electrophysiology was still limited in the 1950s and 60s, with the modern patch clamp technique not available. To investigate axonal conduction with the available electrodes it was necessary to work with a model species that contained an axon large enough for electrode insertion. Nachmannsohn's group used the calmar Loligo pealei for their experiments and one of these experiments tried to block axonal conduction b irreversibly inhibiting the cholinesterases using the potent inhibitor diisopropyl fluorophosphate (DFP). The DFP concentration required to block conduction in the axon turned out to be three orders of magnitude higher than the concentration required to inhibit cholinesterases in solution.
Francis C.G. Hoskin, at that time assistant professor at Columbia University NY, tried to investigate this surprising behavior by using 14C labeled DFP. He was able to show that radioactivity rapidly accumulated in the interior of the axon. But the compound found was not DFP but diisopropyl phosphoric acid. He concluded that the axonal envelope contains a potent enzyme that accounts for the high concentrations of DFP required to block conduction[1].
3D Structures of squid DFPase
- 1e1a This is the original structure solved at 1.8 Å (cryo conditions)
- 1pjx Atomic resolution structure of DFPase solved at 0.85 Å.
- 2gvw Structure solved at at 1.86 Å (room temperature).
- 3byc This is the neutron structure of DFPase solved by joint X-ray and neutron refinement.
- 3kgg X-ray structure of perdeuterated DFPase at 2.1 Å (room temperature).
- 2gvv DFPase in complex with dicyclopentylphosphoroamidate (DcPPA)
- 3li3 DFPase mutant D121E
- 3li4 DFPase mutant N120D/N175D/D229N
- 3li5 DFPase mutant E21Q/N120D/N175D/D229N
- 3hlh DFPase mutant E37A/Y144A/R146A/T195M
- 3hli DFPase mutant E37D/Y144A/R146A/T195M
- 2gvu DFPase mutant D229N/N120D
- 2gvx DFPase mutant D229N/N175D
- 2iax DFPase mutant D232S
- 2iaw DFPase mutant D175D
- 2iav DFPase mutant H287A
- 2iau DFPase mutant W244Y
- 2iat DFPase mutant W244L
- 2ias DFPase mutant W244F
- 2iar DFPase mutant W244H
- 2iaq DFPase mutant S271A
- 2iap DFPase mutant E21Q
- 2iao DFPase mutant E37Q
