TY - JOUR AB - Progress in structural membrane biology has been significantly accelerated by the ongoing 'Resolution Revolution' in cryo electron microscopy (cryo-EM). In particular, structure determination by single particle analysis has evolved into the most powerful method for atomic model building of multisubunit membrane protein complexes. This has created an ever increasing demand in cryo-EM machine time, which to satisfy is in need of new and affordable cryo electron microscopes. Here, we review our experience in using the JEOL CRYO ARM 200 prototype for the structure determination by single particle analysis of three different multisubunit membrane complexes: the Thermus thermophilus V-type ATPase VO complex, the Thermosynechococcus elongatus photosystem I monomer and the flagellar motor LP-ring from Salmonella enterica. AU - Gerle, Christoph AU - Kishikawa, Jun-ichi AU - Yamaguchi, Tomoko AU - Nakanishi, Atsuko AU - Çoruh, Mehmet Orkun AU - Makino, Fumiaki AU - Miyata, Tomoko AU - Kawamoto, Akihiro AU - Yokoyama, Ken AU - Namba, Keiichi AU - Kurisu, Genji AU - Kato, Takayuki ID - 11648 IS - 5 JF - Microscopy KW - Radiology KW - Nuclear Medicine and imaging KW - Instrumentation KW - Structural Biology SN - 2050-5698 TI - Structures of multisubunit membrane complexes with the CRYO ARM 200 VL - 71 ER - TY - JOUR AB - Mica-titania pearlescent pigments (MTs) were previously coated with organic molecules to obtain combination pigments (CPs) for achieving certain improvements or functionalities. Anthocyanins (ACNs) are molecules that can be extracted from natural resources and exhibit color changes via pH modifications of the enclosing medium. The purpose of the study was to produce a new series of CPs by depositing ACNs on MTs at different pH values, to observe the changes in color, and to associate these changes to thermogravimetrically determined deposition efficiencies in light of spectral differences. The extraction and deposition methods were based on aqueous chemistry and were straightforward. The ACN deposition generally increased with increasing pH and correlated with the consistency between the charges of the MT surfaces and the dominant ACN species at a specific pH value. The fluorescence of the CPs was inversely correlated with the deposition quantities invoking the possibility of a quenching effect. AU - Çoruh, Mehmet Orkun AU - Gündüz, Güngör AU - Çolak, Üner AU - Maviş, Bora ID - 10945 IS - 2 JF - Colorants SN - 2079-6447 TI - pH-dependent coloring of combination effect pigments with anthocyanins from Brassica oleracea var. capitata F. rubra VL - 1 ER - TY - JOUR AB - A high-resolution structure of trimeric cyanobacterial Photosystem I (PSI) from Thermosynechococcus elongatus was reported as the first atomic model of PSI almost 20 years ago. However, the monomeric PSI structure has not yet been reported despite long-standing interest in its structure and extensive spectroscopic characterization of the loss of red chlorophylls upon monomerization. Here, we describe the structure of monomeric PSI from Thermosynechococcus elongatus BP-1. Comparison with the trimer structure gave detailed insights into monomerization-induced changes in both the central trimerization domain and the peripheral regions of the complex. Monomerization-induced loss of red chlorophylls is assigned to a cluster of chlorophylls adjacent to PsaX. Based on our findings, we propose a role of PsaX in the stabilization of red chlorophylls and that lipids of the surrounding membrane present a major source of thermal energy for uphill excitation energy transfer from red chlorophylls to P700. AU - Çoruh, Mehmet Orkun AU - Frank, Anna AU - Tanaka, Hideaki AU - Kawamoto, Akihiro AU - El-Mohsnawy, Eithar AU - Kato, Takayuki AU - Namba, Keiichi AU - Gerle, Christoph AU - Nowaczyk, Marc M. AU - Kurisu, Genji ID - 10310 IS - 1 JF - Communications Biology KW - general agricultural and biological Sciences KW - general biochemistry KW - genetics and molecular biology KW - medicine (miscellaneous) SN - 2399-3642 TI - Cryo-EM structure of a functional monomeric Photosystem I from Thermosynechococcus elongatus reveals red chlorophyll cluster VL - 4 ER -