Synthetic cation transport peptides: calcium transport across phospholipid membranes
| العنوان: | Synthetic cation transport peptides: calcium transport across phospholipid membranes |
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| المؤلفون: | Charles M. Deber, Mary E. M. Young, Jean Tom-Kun |
| المصدر: | Biochemistry. 19:6194-6198 |
| بيانات النشر: | American Chemical Society (ACS), 1980. |
| سنة النشر: | 1980 |
| مصطلحات موضوعية: | chemistry.chemical_classification, Binding Sites, biology, Chemistry, Stereochemistry, Vesicle, Sodium, Phospholipid, chemistry.chemical_element, Biological Transport, Peptide, Calcium, Peptides, Cyclic, Biochemistry, Membrane Lipids, Mitochondrial membrane transport protein, chemistry.chemical_compound, Membrane, Cations, biology.protein, Phospholipids, Cation transport |
| الوصف: | Molecular aspects of peptide-mediated calcium transport are examined through the study of the cation transport properties of a series of synthetic cyclic octapeptides. These peptides, of general structure cyclo[Glu(OR1)-Sar-Gly-(N-R2)Gly]2 (R1 = H or benzyl ester; R2 = cyclohexyl, n-hexyl, or n-decyl) (and an Asp analogue), contain central binding cavities of geometry and dimensions similar to calcium-binding sites in proteins. Transport in Pressman cells ("thick liquid membranes") demonstrated the ionophorous activity of the synthetic peptides; among physiologically abundant cations, the order of selectivity was Ca2+ greater than Na+, K+ much greater than Mg2+. Cation competition studies further showed that cyclo[Glu(OBz)-Sar-Gly-(N-cyclohexyl)Gly]2 (CYCLEX-2E) is essentially a calcium-specific transport peptide whenever calcium is present. When the CYCLEX-2E peptide was added to a suspension of 45Ca2+-loaded sonicated phosphatidylcholine (PC) vesicles in a dialysis sac, the vesicles were completely emptied of internal calcium. Controls using [14C]sucrose established that CYCLEX-2E caused no nonspecific membrane damage. Calcium efflux experiments using several salts of calcium (including 36C1-, [14C]acetate, [14C]succinate, and 35SO4(2-)) suggested that these anions do not specifically accompany the Ca2+-peptide active transporting species across the phospholipid membrane. However, when 45Ca2+-loaded PC vesicles were suspended in mental-free buffer and treated with CYCLEX-2E peptide, calcium efflux did not occur until calcium or sodium chloride was added to the external medium. |
| تدمد: | 1520-4995 0006-2960 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ef28c1c24b18282715070655bbf07cc9 https://doi.org/10.1021/bi00567a038 |
| رقم الأكسشن: | edsair.doi.dedup.....ef28c1c24b18282715070655bbf07cc9 |
| قاعدة البيانات: | OpenAIRE |
Find this issue from the American Chemical Society | تدمد: | 15204995 00062960 |
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