Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

SCP2 and SCP3 are major protein components of the lateral elements (LEs) of synaptonemal complexes (SCs) of the rat, with Mrs of 173, 000 and 30,000. We performed a detailed immunocytochemical comparison of the localization of SCP2 and SCP3 within SCs at the electron microscopic level. The ultrastructural localization of SCP2 and SCP3 was analyzed by immunogold labeling of two types of preparations, namely surface-spread spermatocytes and ultrathin sections of Lowicryl-embedded testicular tissue of the rat. For each of the antisera used, the distribution of immunogold label over SCs in surface-spread spermatocytes differed significantly from the distribution of label on sections. We attributed this difference to artifacts caused by the surface-spreading technique, and therefore we relied on sections for the precise localization of epitopes. On sections, the distribution of label obtained with two antisera against nonoverlapping, widely separated fragments of SCP2 did not differ significantly. There was a small but significant difference between the labeling pattern obtained with an anti-SCP3 serum and the pattern obtained with either of the two antisera against fragments of SCP2; although for all three antisera the peak of the immunogold label coincided with the center of the LE, the distributions of label obtained with the antisera against fragments of SCP2 were asymmetrical, with a shoulder at the inner side of the LE, whereas the distribution of label obtained with anti-SCP3 serum was symmetrical. Furthermore, we observed fuzzy connections between the LEs that were labeled by anti-SCP2 but not anti-SCP3 antibodies. It is possible that labeling of these fuzzy bridges caused the shoulder in the gold label distributions obtained with anti-SCP2 antibodies.
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PMID:Localization of SCP2 and SCP3 protein molecules within synaptonemal complexes of the rat. 993 7

We applied protein-mediated lipid transfer using recombinant His-tagged pro-sterol carrier protein 2 (pro-SCP2) to prepare asymmetrical membrane vesicles (AMV) featuring an unequal transmembrane distribution of the negative phospholipid egg-phosphatidylglycerol (EPG). Pure egg-phosphatidylcholine (EPC) vesicles were used as the acceptor and EPC:EPG 90:10 mol % vesicles as the donor populations. The changes in surface charge during EPG transfer were used to quantify the degree of asymmetry by free-flow electrophoresis (FFE). The relative deflection in FFE correlated with EPG content in the outer monolayer (x(EPG)). The initial transfer rates and first order rate constants for the transfer process were determined. The addition of pro-SCP2 at a molar protein-to-lipid ratio R(P/L) of (15-20) x 10(-5) accelerated the EPG transfer to half-times of between 2 and 3 h. Thus, the transmembrane redistribution of EPG by flip-flop, which reduces the degree of asymmetry and occurs at half-times of tens of hours, was minimized during the transfer process. We investigated the influence of membrane curvature on the transfer rate using 50 and 100 nm vesicles with very low size distribution widths (RSD of 13-17%). Transfer occurred with a 55.7% higher initial rate between the smaller vesicles. The use of equally sized acceptor and donor populations of such narrow size distributions was shown to be important for the preparation of AMV with a uniform degree of asymmetry. Under these conditions, AMV were obtained after less than 3 h by preparative FFE separation. In the case of the acceptor vesicles, EPG transfer increased x(EPG) to 3 mol %, whereas it was reduced to 6 mol % in the donor vesicles.
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PMID:Lipid transfer mediated by a recombinant pro-sterol carrier protein 2 for the accurate preparation of asymmetrical membrane vesicles requires a narrow vesicle size distribution: a free-flow electrophoresis study. 2009 35