Mitrocomin from the jellyfish Mitrocoma cellularia with deleted C-terminal tyrosine reveals a higher bioluminescence activity compared to wild type photoprotein
| Autor: | Pavel V. Natashin, Natalia P. Malikova, Elena V. Eremeeva, Svetlana V. Markova, Zhi-Jie Liu, Chongyun Cheng, Ludmila P. Burakova, Eugene S. Vysotski |
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| Rok vydání: | 2016 |
| Předmět: |
Models
Molecular 0301 basic medicine Gene isoform Luminescence Protein Conformation Population Biophysics Photoprotein Aequorin Biology Crystallography X-Ray 03 medical and health sciences Complementary DNA Animals Bioluminescence Radiology Nuclear Medicine and imaging Amino Acid Sequence Cloning Molecular education Sequence Deletion education.field_of_study Radiation Radiological and Ultrasound Technology Calcium-Binding Proteins Wild type Molecular biology Luminescent Proteins 030104 developmental biology Biochemistry biology.protein Tyrosine Calcium Light emission |
| Zdroj: | Journal of Photochemistry and Photobiology B: Biology. 162:286-297 |
| ISSN: | 1011-1344 |
| Popis: | The full-length cDNA genes encoding five new isoforms of Ca2 +-regulated photoprotein mitrocomin from a small tissue sample of the outer bell margin containing photocytes of only one specimen of the luminous jellyfish Mitrocoma cellularia were cloned, sequenced, and characterized after their expression in Escherichia coli and subsequent purification. The analysis of cDNA nucleotide sequences encoding mitrocomin isoforms allowed suggestion that two isoforms might be the products of two allelic genes differing in one amino acid residue (64R/Q) whereas other isotypes appear as a result of transcriptional mutations. In addition, the crystal structure of mitrocomin was determined at 1.30 A resolution which expectedly revealed a high similarity with the structures of other hydromedusan photoproteins. Although mitrocomin isoforms reveal a high degree of identity of amino acid sequences, they vary in specific bioluminescence activities. At that, all isotypes displayed the identical bioluminescence spectra (473–474 nm with no shoulder at 400 nm). Fluorescence spectra of Ca2 +-discharged mitrocomins were almost identical to their light emission spectra similar to the case of Ca2 +-discharged aequorin, but different from Ca2 +-discharged obelins and clytin which fluorescence is red-shifted by 25–30 nm from bioluminescence spectra. The main distinction of mitrocomin from other hydromedusan photoproteins is an additional Tyr at the C-terminus. Using site-directed mutagenesis, we showed that this Tyr is not important for bioluminescence because its deletion even increases specific activity and efficiency of apo-mitrocomin conversion into active photoprotein, in contrast to C-terminal Pro of other photoproteins. Since genes in a population generally exist as different isoforms, it makes us anticipate the cloning of even more isoforms of mitrocomin and other hydromedusan photoproteins with different bioluminescence properties. |
| Databáze: | OpenAIRE |
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