caa a22 4500 606207651 CHVBK 20210128101018.0 cr unu---uuuuu 210128e20150701xx s 000 0 eng 10.1007/s00425-015-2294-4 doi (NATIONALLICENCE)springer-10.1007/s00425-015-2294-4 Characterization of unusual truncated hemoglobins of Chlamydomonas reinhardtii suggests specialized functions [Elektronische Daten] [Dennis Huwald, Peer Schrapers, Ramona Kositzki, Michael Haumann, Anja Hemschemeier] Main conclusion : Annotated hemoglobin genes in Chlamydomonas reinhardtii form functional globins, despite unusual architectures. Spectral characteristics show subtle biochemical differences. Multiple globins might help the alga to cope with its versatile environment. The unicellular green alga C. reinhardtii is a photosynthetic, often soil-dwelling organism, subjected to a changeable environment in nature. The alga contains 12 genes encoding so-called truncated hemoglobins that feature a two-on-two helical fold instead of the three-on-three helix arrangement of the long-studied vertebrate globins or plant symbiotic and non-symbiotic hemoglobins. In plants, non-symbiotic hemoglobins often play a role in acclimation to stress, and we could show recently that one of the C. reinhardtii globin genes is vital for anoxic growth. Here, three further globin encoding transcripts (Cre16.g661000.t1.1, Cre16.g661300.t2.1 and Cre16.g662750.t1.2) were heterologously expressed along with the recently studied THB1. UV-Vis and X-ray absorption spectroscopy analyses show that the sequences indeed encode functional hemoglobins, despite their uncommon primary sequences, which include long C-termini without any predictable function, or a split heme-binding domain. The proteins show some variations regarding the coordination of the heme iron or the interaction with diatomic ligands, indicating different functionalities. The respective transcripts are not responsive to the nitrogen source, in contrast to results reported for THB1, but they accumulate in darkness. This work advances experimental data on the very large globin family in general, and, more specifically, on hemoglobins in photosynthetic organisms. Springer-Verlag Berlin Heidelberg, 2015 Acclimation nationallicence Heterotrophy nationallicence Hypoxia nationallicence Nitric oxide nationallicence Truncated hemoglobin nationallicence X-ray absorption spectroscopy nationallicence BVS : Bondvalence sum nationallicence DCMU : 3-(3,4-Dichlorophenyl)-1,1-dimethylurea nationallicence EXAFS : Extended X-ray absorption fine structure nationallicence Hb : Hemoglobin nationallicence 2/2Hb : Hemoglobin of the 2-on-2-helices fold ("truncated hemoglobin”) nationallicence 3/3Hb : Hemoglobin of the 3-on-3-helices (myoglobin-) fold nationallicence Mb : Myoglobin nationallicence NOD : Nitric oxide dioxygenase nationallicence qRT-PCR : Quantitative reverse transcription polymerase chain reaction nationallicence RNA-Seq : RNA sequencing nationallicence rTHB/rTHB-s : Recombinant 2/2Hb/recombinant 2/2Hb lacking the C-terminus nationallicence XANES : X-ray absorption near edge structure nationallicence XAS : X-ray absorption spectroscopy nationallicence Huwald Dennis Work Group Photobiotechnology, Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, ND2/134, 44801, Bochum, Germany aut Schrapers Peer Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut Kositzki Ramona Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut Haumann Michael Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut Hemschemeier Anja Work Group Photobiotechnology, Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, ND2/134, 44801, Bochum, Germany aut Planta Springer Berlin Heidelberg 242/1(2015-07-01), 167-185 0032-0935 242:1<167 2015 242 425 https://doi.org/10.1007/s00425-015-2294-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-015-2294-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Huwald Dennis Work Group Photobiotechnology, Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, ND2/134, 44801, Bochum, Germany aut NATIONALLICENCE 700 1- Schrapers Peer Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut NATIONALLICENCE 700 1- Kositzki Ramona Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut NATIONALLICENCE 700 1- Haumann Michael Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany aut NATIONALLICENCE 700 1- Hemschemeier Anja Work Group Photobiotechnology, Department of Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University of Bochum, Universitätsstr. 150, ND2/134, 44801, Bochum, Germany aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 242/1(2015-07-01), 167-185 0032-0935 242:1<167 2015 242 425