Native and promiscuous catalytic activities of flavin-dependent Old Yellow Enzymes (OYEs) reported to date are initiated by the reduced flavin upon electron transfer. As a rare exception, isomerization nonactivated C═C bond was shown be hydride-independent with two nonstereoselective yeast OYEs. Here, we report asymmetric prochiral model substrate, γ-methyl β,γ-butenolide, corresponding (R)- (S...

In Escherichia coli, FkpA, PpiA, PpiD, and SurA are the four known periplasmic cis-trans prolyl isomerases. These isomerases facilitate proper protein folding by increasing the rate of transition of proline residues between the cis and trans states. Genetic inactivation of all four periplasmic isomerases resulted in a viable strain that exhibited a decreased growth rate and increased susceptibi...

Peptidyl-prolyl cis-trans-isomerases are a highly conserved family of immunophilins. The three peptidyl-prolyl cis-trans-isomerase subfamilies are cyclophilins, FK-506-binding proteins, and parvulins. Peptidyl-prolyl cis-trans-isomerases are expressed in multiple human tissues and regulate different cellular functions, e.g. calcium handling, protein folding, and gene expression. Moreover, these...

Newcastle disease virus (NDV) fusion (F) protein directs membrane fusion, which is required for virus entry and cell-cell fusion. We have previously shown that free thiols are present in cell surface-expressed NDV F protein and that blocking the production of free thiols by thiol-disulfide exchange inhibitors inhibited the membrane fusion mediated by F protein (J Virol. 81:2328-2339, 2007). Ext...

Protein disulfide isomerase (PDI), ERp5, and ERp57, among perhaps other thiol isomerases, are important for the initiation of thrombus formation. Using the laser injury thrombosis model in mice to induce in vivo arterial thrombus formation, it was shown that thrombus formation is associated with PDI secretion by platelets, that inhibition of PDI blocked platelet thrombus formation and fibrin ge...

Prolyl isomerases are enzymes that catalyze cis-trans isomerization of peptidyl-prolyl bonds and span three structurally unrelated protein families: the cyclophilins, FKBPs, and parvulins. The genome of the budding yeast Saccharomyces cerevisiae encodes eight different cyclophilins (Cpr1 to Cpr8), four FKBPs (Fpr1 to Fpr4), and a single parvulin (Ess1). Remarkably, two of these proteins, cyclop...

Peptidylprolyl isomerases have been implicated in chromatin regulation through their association with histones, chromatin-modifying enzymes and DNA-binding transcription factors. As with other post-translational modifications to proteins, a mechanistic understanding of the regulation of biological processes is fostered by loss-of-function studies both in vitro and in vivo. For peptidylprolyl is...