Graz University of Technology Archives - Astrobiology

The prototypical PAS (grass green)-GAF (green)-PHY (dark green)-output module (grey-blue) arrangement of bacteriophytochromes is depicted. The N-terminal segment (NTS, blue) and the PHY tongue (dark green β sheets or blue-green helix) are shown in their light state-dependent conformations. The BV cofactor is colored in orange-red (Pr state) or brown-red (Pfr state). (A) Prototypical Pr resting state. (B) Red light-illuminated non-canonical activated state (IsPadC model) featuring an asymmetric Pr-Pfr heterodimer assembly. (C) Red light-illuminated canonical activated state (AfAgp1 model) featuring a Pfr-Pfr homodimer assembly. (D) Chemical structure of the BV cofactor covalently bound to BphPs. Red light isomerizes the C15 = C16 double bond, causing a D-ring flip and stabilization of the 15E configuration by surrounding residues in Pfr. (E) Spectral characteristics of a non-canonical model phytochrome (IsPadC) with Pr (red) and illuminated state trace (brown-red) with incomplete conversion to Pfr. (F) UV-vis spectrum of a canonical model phytochrome (AfAgp1; data from ref.19) with more complete Pfr formation. -- Cell

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Understanding Protein Form And Function Better At TU Graz

by Keith CowingDecember 30, 2025December 30, 2025

Proteins are among the most important building blocks of nature and play a central role in biological processes in all organisms.