TY  - JOUR
A1  - Dunce, James M.
A1  - Milburn, Amy E.
A1  - Gurusaran, Manickam
A1  - da Cruz, Irene
A1  - Sen, Lee T.
A1  - Benavente, Ricardo
A1  - Davies, Owen R.
T1  - Structural basis of meiotic telomere attachment to the nuclear envelope by MAJIN-TERB2-TERB1
JF  - Nature Communications
N2  - Meiotic chromosomes undergo rapid prophase movements, which are thought to facilitate the formation of inter-homologue recombination intermediates that underlie synapsis, crossing over and segregation. The meiotic telomere complex (MAJIN, TERB1, TERB2) tethers telomere ends to the nuclear envelope and transmits cytoskeletal forces via the LINC complex to drive these rapid movements. Here, we report the molecular architecture of the meiotic telomere complex through the crystal structure of MAJIN-TERB2, together with light and X-ray scattering studies of wider complexes. The MAJIN-TERB2 2:2 hetero-tetramer binds strongly to DNA and is tethered through long flexible linkers to the inner nuclear membrane and two TRF1-binding 1:1 TERB2-TERB1 complexes. Our complementary structured illumination microscopy studies and biochemical findings reveal a telomere attachment mechanism in which MAJIN-TERB2-TERB1 recruits telomere-bound TRF1, which is then displaced during pachytene, allowing MAJIN-TERB2-TERB1 to bind telomeric DNA and form a mature attachment plate.
KW  - DNA
KW  - meiosis
KW  - proteins
KW  - super-resolution microscopy
KW  - X-ray crystallography
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226416
VL  - 9
ER  - 
TY  - JOUR
A1  - Kraus, Michael
A1  - Grimm, Clemens
A1  - Seibel, Jürgen
T1  - Reversibility of a Point Mutation Induced Domain Shift: Expanding the Conformational Space of a Sucrose Phosphorylase
JF  - Scientific Reports
N2  - Despite their popularity as enzyme engineering targets structural information about Sucrose Phosphorylases remains scarce. We recently clarified that the Q345F variant of Bifidobacterium adolescentis Sucrose Phosphorylase is able to accept large polyphenolic substrates like resveratrol via a domain shift. Here we present a crystal structure of this variant in a conformation suitable for the accommodation of the donor substrate sucrose in excellent agreement with the wild type structure. Remarkably, this conformation does not feature the previously observed domain shift which is therefore reversible and part of a dynamic process rather than a static phenomenon. This crystallographic snapshot completes our understanding of the catalytic cycle of this useful variant and will allow for a more rational design of further generations of Sucrose Phosphorylase variants.
KW  - biocatalysis
KW  - X-ray crystallography
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224845
VL  - 8
ER  - 
TY  - JOUR
A1  - Scheib, Ulrike
A1  - Broser, Matthias
A1  - Constantin, Oana M.
A1  - Yang, Shang
A1  - Gao, Shiqiang
A1  - Mukherjee, Shatanik
A1  - Stehfest, Katja
A1  - Nagel, Georg
A1  - Gee, Christine E.
A1  - Hegemann, Peter
T1  - Rhodopsin-cyclases for photocontrol of cGMP/cAMP and 2.3 Å structure of the adenylyl cyclase domain
JF  - Nature Communications
N2  - The cyclic nucleotides cAMP and cGMP are important second messengers that orchestrate fundamental cellular responses. Here, we present the characterization of the rhodopsinguanylyl cyclase from Catenaria anguillulae (CaRhGC), which produces cGMP in response to green light with a light to dark activity ratio > 1000. After light excitation the putative signaling state forms with tau = 31 ms and decays with tau = 570 ms. Mutations (up to 6) within the nucleotide binding site generate rhodopsin-adenylyl cyclases (CaRhACs) of which the double mutated YFP-CaRhAC (E497K/C566D) is the most suitable for rapid cAMP production in neurons. Furthermore, the crystal structure of the ligand-bound AC domain (2.25 angstrom) reveals detailed information about the nucleotide binding mode within this recently discovered class of enzyme rhodopsin. Both YFP-CaRhGC and YFP-CaRhAC are favorable optogenetic tools for non-invasive, cell-selective, and spatio-temporally precise modulation of cAMP/cGMP with light.
KW  - Enzymes
KW  - Molecular biophysics
KW  - Molecular neuroscience
KW  - X-ray crystallography
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228517
VL  - 9
ER  -