Blaauwen, T. den

Driessen, A.J.M.

English

Dissertations of the University of Groningen

   University of GroningenConformational Changes in the Bacterial Translocase Subunit SecABlaauwen, T. den; Driessen, A.J.M.IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1996Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Blaauwen, T. D., & Driessen, A. J. M. (1996). Conformational Changes in the Bacterial TranslocaseSubunit SecA.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 05-06-2022A3 Structural dynamics P-A3-01 MOLECULAR DYNAMICAL THEORY FOR SPONTANEOUS EMISSION OF BIO - PHOTONS IN THE LIVING SYSI%MS DANG XIAO - FENG Dept. d physics, Sourhwar hmitute lw Nsticditier , C&s& .610(x1. and Insti~e of Atcmic and Mddu physics. Sehusn Unim univcniy. c2m@$u 610065, china Pltrpo~e: Many experiments show that the bio - photon emission including the4 radiation and 7 - photons of the Living systems is a general and important biological phaomemm. We propose here a theory of mdecdur biology for the emission of bio - photons . Metheds : We think that the bii - photon emission come frcm the transition of bonding electron and diiplacement of active nuclei and non - linear vibration of mdecular chaii resulting from the sditons excited by the intnmdeculru lomlized flwtion and the deformation of structure and conformntiott of mdpxdar chains caused by the energy released in ATP hydmlpis in biomecmmdecula with biological temperature. The Hamiltonian and Wave function in our theory 10>=~~cl+‘R(t)~*.)QP[~((c(t)d-$(t)s)l.~ . JE;T’O’ RCS&S: applying non - linear quantum theory we find out the Intensity of bio- photon emission to be w’g[-%mJ,m-G.~T;J -~T;f,Jrn]S”‘((q-r)t/2)/(;o-r)‘( [[A’(T)Cd(&h (u(vt-q)))U(E) +~~~~1=1:]*+~‘(~)n(~)l~‘(tlh(” condlU!3iOllS: with the help of this result, we can explain all phornmena and properties of bio - photon emission obtained from experiments. P-A3-03 PHOTOSENSING IN EUBACTERIA: T-S ISOMERIZATION OF THE CHROMOPHORE OF PYP KORT, R., CRD&URD, W. AND HEUINGWERF, K.J. E.C. Slater Institute, University of Amsterdam (NL) Purpose: Photoactive yellow protein (PYP) is a cytosolic eubacterial blue-light photosensor with a rhodopsin-like photocycle. The photochemical basis of the photocycle of PYP has been investigated to find a rationale for the high similarity of its photocycle to that of sensory rhodopsins, in spite of great structural differences. Methods: The p-coumaric acid chromophore was extracted fiorn the ground state of PYP (PG) as well as from the blue-shifted photocycle intermediate (PB). Extracts were analyzed by zone capillary electrophoresis and ‘H-Nh4R spectroscopy. Results: Analysis of the chromophore extracts from pG and pB demonstrated that the chromophtic group of PYP isomer&s &om tram to cis p-couma- ric acid while progressing through the photocycle. Conclusions: These results contribute to the under- standing of the similarity in photocycle between PYF and sensory rhodopsins and show that also in Bacteria, so in all three domains of life, photosensing occurs by a common photochemical basis: isomerization of a chrornophore double bond. P-A342 CONFORMATIONAL CHANGES IN THE BACTERIAL TRANSWCASE SUBUNIT SECA DEN BLAAUWEN T., DRIESSEN A.J.M. Groningen Biomol. Sci. and Biotech. Institute. Univ. of Groningen (NL) The homodimeric SecA protein is the peripheral subunit of the preprotein franslocase in bacteria. It binds the preprotein and promotes its translocation across the bacterial cytoplasmic membrane by nucleotide modulated co-insertion and de-insertion into the membrane. SecA has a high affinity nucleotide binding site (NBS-I) in its amino terminal domain and a low affinity NBS (II) in its carboxy-terminal domain. The conformations of the nucleotide bound states of SecA were studied by site directed tryptophan fluorescence spectroscopy, tryptic digestion, differential scanning calorimetry and dynamic light scattering. SecA unfolds as a two domain protein. ADP binding to NBS-I increases the interaction between these domains, whereas the non-hydrolysable ATP analog AMP-PNP does not influence this interaction. ADP binding to both sites induces a more compact state, which is though to resemble the membrane de-inserted state of SecA. AMP-PNP induces a more extended conformation, which could resemble the membrane inserted state. P-A344 CONFORMATIONS OF PROLINE DIPEP- TIDE STUDIED BY AB INITKO METHOD KANGYK Dept. of Chemistry, Chungbuk Natl. Univ. (Korea) Purpose: The low-ener conformations of trans- and cis-Ac-Pro- N%4 e with down and up puckerings are studied in order to investigate the preference of the puckering of pyrrolidine ring for the preceding imide bond. Methods: All ab initio calculations were carried out using the Gaussian 90 and 92 molecular or- bital packages. Full geometry optimizations were performed at the direct HF/SCF level with the 6-3 lG** basis set. Single-point MP2 calcu- lations were also performed on the optimized conformations with the same basis set. Results: The intramolecularly hydrogen-bonded C7 conformer is found to be most preferred. The down puckering seems to be about 1.5 kcal/mol more stable than the up puckering at the HF/6- 3 1 G** and Mp2/6-3 1 G** levels. The optimized structural parameters are in general consistent with X-ray structures of peptides. Conclusions: The preference and po ulation for down and up puckered structures wt 4 the tram and cis imide bonds calculated here agree rea- sonably with the results obtained from the analysis of X-ray structures of roteins. The de- gree of scribed \ uckering for each con P ormer is well de- y puckering amplitudes. 40 

Conformational Changes in the Bacterial Translocase Subunit SecA

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Conformational Changes in the Bacterial Translocase Subunit SecA

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