caa a22 4500 445821531 CHVBK 20180317145245.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s00239-010-9416-1 doi (NATIONALLICENCE)springer-10.1007/s00239-010-9416-1 Amino Acid Compositional Shifts During Streptophyte Transitions to Terrestrial Habitats [Elektronische Daten] [Richard Jobson, Yin-Long Qiu] Across the streptophyte lineage, which includes charophycean algae and embryophytic plants, there have been at least four independent transitions to the terrestrial habitat. One of these involved the evolution of embryophytes (bryophytes and tracheophytes) from a charophycean ancestor, while others involved the earliest branching lineages, containing the monotypic genera Mesostigma and Chlorokybus, and within the Klebsormidiales and Zygnematales lineages. To overcome heat, water stress, and increased exposure to ultraviolet radiation, which must have accompanied these transitions, adaptive mechanisms would have been required. During periods of dehydration and/or desiccation, proteomes struggle to maintain adequate cytoplasmic solute concentrations. The increased usage of charged amino acids (DEHKR) may be one way of maintaining protein hydration, while increased use of aromatic residues (FHWY) protects proteins and nucleic acids by absorbing damaging UV, with both groups of residues thought to be important for the stabilization of protein structures. To test these hypotheses we examined amino acid sequences of orthologous proteins representing both mitochondrion- and plastid-encoded proteomes across streptophytic lineages. We compared relative differences within categories of amino acid residues and found consistent patterns of amino acid compositional fluxuation in extra-membranous regions that correspond with episodes of terrestrialization: positive change in usage frequency for residues with charged side-chains, and aromatic residues of the light-capturing chloroplast proteomes. We also found a general decrease in the usage frequency of hydrophobic, aliphatic, and small residues. These results suggest that amino acid compositional shifts in extra-membrane regions of plastid and mitochondrial proteins may represent biochemical adaptations that allowed green plants to colonize the land. Springer Science+Business Media, LLC, 2010 Streptophyte nationallicence Adaptation nationallicence Amino acid nationallicence Embryophyte nationallicence Terrestrialization nationallicence Jobson Richard Department of Ecology and Evolutionary Biology, University of Michigan, 48109-1048, Ann Arbor, MI, USA aut Qiu Yin-Long Department of Ecology and Evolutionary Biology, University of Michigan, 48109-1048, Ann Arbor, MI, USA aut Journal of Molecular Evolution Springer-Verlag 72/2(2011-02-01), 204-214 0022-2844 72:2<204 2011 72 239 https://doi.org/10.1007/s00239-010-9416-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00239-010-9416-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jobson Richard Department of Ecology and Evolutionary Biology, University of Michigan, 48109-1048, Ann Arbor, MI, USA aut NATIONALLICENCE 700 1- Qiu Yin-Long Department of Ecology and Evolutionary Biology, University of Michigan, 48109-1048, Ann Arbor, MI, USA aut NATIONALLICENCE 773 0- Journal of Molecular Evolution Springer-Verlag 72/2(2011-02-01), 204-214 0022-2844 72:2<204 2011 72 239 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer