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University of Nebraska - Lincoln

Department of Biochemistry: Faculty Publications

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Membrane protein

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Full-Text Articles in Life Sciences

Structural Basis For Clostridium Perfringens Enterotoxin Targeting Of Claudins At Tight Junctions In Mammalian Gut, Alex J. Vecchio, Sewwandi S. Rathnayake, Robert M. Stroud Apr 2021

Structural Basis For Clostridium Perfringens Enterotoxin Targeting Of Claudins At Tight Junctions In Mammalian Gut, Alex J. Vecchio, Sewwandi S. Rathnayake, Robert M. Stroud

Department of Biochemistry: Faculty Publications

The bacterium Clostridium perfringens causes severe, sometimes lethal gastrointestinal disorders in humans, including enteritis and enterotoxemia. Type F strains produce an enterotoxin (CpE) that causes the third most common foodborne illness in the United States. CpE induces gut breakdown by disrupting barriers at cell–cell contacts called tight junctions (TJs), which are formed and maintained by claudins. Targeted binding of CpE to specific claudins, encoded by its C-terminal domain (cCpE), loosens TJ barriers to trigger molecular leaks between cells. Cytotoxicity results from claudin-bound CpE complexes forming pores in cell membranes. In mammalian tissues, ∼24 claudins govern TJ barriers—but the basis for …


Structural Basis For Clostridium Perfringens Enterotoxin Targeting Of Claudins At Tight Junctions In Mammalian Gut, Alex J. Vecchio, Sewwandi S. Rathnayake, Robert M. Stroud Feb 2021

Structural Basis For Clostridium Perfringens Enterotoxin Targeting Of Claudins At Tight Junctions In Mammalian Gut, Alex J. Vecchio, Sewwandi S. Rathnayake, Robert M. Stroud

Department of Biochemistry: Faculty Publications

The bacterium Clostridium perfringens causes severe, sometimes lethal gastrointestinal disorders in humans, including enteritis and enterotoxemia. Type F strains produce an enterotoxin (CpE) that causes the third most common foodborne illness in the United States. CpE induces gut breakdown by disrupting barriers at cell–cell contacts called tight junctions (TJs), which are formed and maintained by claudins. Targeted binding of CpE to specific claudins, encoded by its C-terminal domain (cCpE), loosens TJ barriers to trigger molecular leaks between cells. Cytotoxicity results from claudin-bound CpE complexes forming pores in cell membranes. In mammalian tissues, 24 claudins govern TJ barriers—but the basis for …


Endoplasmic Reticulum-Associated Degradation Of Pca1p, A Polytopic Protein, Via Interaction With The Proteasome At The Membrane, Nathan Smith, David J. Adle, Miaoyun Zhao, Xiaojuan Quin, Heejeong Kim, Jaekwon Lee Jan 2016

Endoplasmic Reticulum-Associated Degradation Of Pca1p, A Polytopic Protein, Via Interaction With The Proteasome At The Membrane, Nathan Smith, David J. Adle, Miaoyun Zhao, Xiaojuan Quin, Heejeong Kim, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Endoplasmic reticulum-associated degradation (ERAD) plays a critical role for destruction of terminally misfolded proteins at the secretory pathway. The system also regulates expression levels of several proteins such as Pca1p, a cadmium exporter in yeast. To gain better insight into the mechanisms underlying ERAD of Pca1p and other polytopic proteins by the proteasome in the cytosol, our study determined the roles for the molecular factors of ERAD in dislodging Pca1p from the ER. Inactivation of the 20S proteasome leads to accumulation of ubiquitinylated Pca1p in the ER membrane, suggesting a role for the proteasome in extraction of Pca1p from the …


Photosynthetic Electron Transport In Genetically Altered Photosystem Ii Reaction Centers Of Chloroplasts, Robin A. Roffey, John H. Golebeck, C. Russ Hille, Richard T. Sayre Jan 1991

Photosynthetic Electron Transport In Genetically Altered Photosystem Ii Reaction Centers Of Chloroplasts, Robin A. Roffey, John H. Golebeck, C. Russ Hille, Richard T. Sayre

Department of Biochemistry: Faculty Publications

Using a cotransformation system to identify chloroplast transformants in Chlamydomonas reinhardtii, we converted histidine-195 of the photosystem H reaction center D1 protein to a tyrosine residue. The mutants were characterized by a reduced quantum efficiency for photosynthetic oxygen evolution, which varied in a pH-dependent manner, a reduced capacity to oxidize artificial donors to photosystem II, and P680+) reduction kinetics (microsecond) that were essentially similar to wild type. In addition, a dark-stable radical was detected by ESR in mutant photosystem II particles but not in wild-type particles. This radical was similar in g value and lineshape to chlorophyll …