4HEH

Crystal structure of AppA SCHIC domain from Rb. sphaeroides

Summary for 4HEH

• Entry DOI: 10.2210/pdb4heh/pdb
• Descriptor: AppA protein (2 entities in total)
• Functional Keywords: redox sensing, heme binding, metal binding protein
• Biological source: Rhodobacter sphaeroides
• Total number of polymer chains: 2
• Total formula weight: 45526.70

Authors

Dragnea, V.,Yin, L.,Dann III, C.E.,Bauer, C.E. (deposition date: 2012-10-03, release date: 2013-09-18, Last modification date: 2024-02-28)

Primary citation

Yin, L.,Dragnea, V.,Feldman, G.,Hammad, L.A.,Karty, J.A.,Dann III, C.E.,Bauer, C.E.
Redox and light control the heme-sensing activity of AppA.
MBio, 4:e00563-e00513, 2013

PubMed Abstract: The DNA binding activity of the photosystem-specific repressor PpsR is known to be repressed by the antirepressor AppA. AppA contains a blue-light-absorbing BLUF domain and a heme-binding SCHIC domain that controls the interaction of AppA with PpsR in response to light and heme availability. In this study, we have solved the structure of the SCHIC domain and identified the histidine residue that is critical for heme binding. We also demonstrate that dark-adapted AppA binds heme better than light-excited AppA does and that heme bound to the SCHIC domain significantly reduces the length of the BLUF photocycle. We further show that heme binding to the SCHIC domain is affected by the redox state of a disulfide bridge located in the Cys-rich carboxyl-terminal region. These results demonstrate that light, redox, and heme are integrated inputs that control AppA's ability to disrupt the DNA binding activity of PpsR.

PubMed: 23982072
DOI: 10.1128/mBio.00563-13

Experimental method

X-RAY DIFFRACTION (2.05 Å)