Kheraiceras Spath (Ammonoidea): New forms and records from the Middle Jurassic sequence of the Indian Subcontinent

Volume: 4Start Page: 205End Page: 22

Purification and characterization of a gelatinolytic serine protease from the seeds of ash gourd <em>Benincasa hispida</em> (Thunb.) Cogn.

77-87In Ayurveda, Benincasa hispida (Thunb.) Cogn. (Ash gourd) was recommended for management of diabetes, peptic ulcer, and other diseases. This plant is rich in proteolytic enzymes and proteases have wide application in food and laundry industry. Therefore, the search for new potential plant proteases continues. A soluble gelatinolytic plant serine protease (AG2) had been purified from the seeds of Benincasa hispida. The molecular mass of the monomer was estimated to be about 11 kDa by SDS-PAGE and 11211.1 Da by MALDI-TOF. The protease activity was strongly inhibited by PMSF only but not at all by soyabean trypsin inhibitor and resists autodigestion. Thus AG2 belongs to subtilisin family. The optimum pH and temperature are 10.0 and 30°C respectively. This protease was quite stable in presence of a cationic surfactant, an oxidizing agent and in basic pH medium. The protease AG2 can hydrolyze casein, azoalbumin and TAME but it was inert towards BAPNA. The kinetic parameters Km and Vmax were 0.117 ± 0.00067 mM and 470.592 ± 0.631 unit mg-1 min-1 respectively using casein as substrate. The CD spectrum showed it as a typical α/β class of protease. The N-terminal sequence of first 17 amino acid residues (MQQFFNEPSSLLIVVVR) is unique in nature

<i>In Vivo</i> Encapsulation of Nucleic Acids Using an Engineered Nonviral Protein Capsid

In Nature, protein capsids function as molecular containers for a wide variety of molecular cargoes. Such containers have great potential for applications in nanotechnology, which often require encapsulation of non-native guest molecules. Charge complementarity represents a potentially powerful strategy for engineering novel encapsulation systems. In an effort to explore the generality of this approach, we engineered a nonviral, 60-subunit capsid, lumazine synthase from <i>Aquifex aeolicus</i> (AaLS), to act as a container for nucleic acid. Four mutations were introduced per subunit to increase the positive charge at the inner surface of the capsid. Characterization of the mutant (AaLS-pos) revealed that the positive charges lead to the uptake of cellular RNA during production and assembly of the capsid <i>in vivo</i>. Surprisingly, AaLS-pos capsids were found to be enriched with RNA molecules approximately 200–350 bases in length, suggesting that this simple charge complementarity approach to RNA encapsulation leads to both high affinity and a degree of selectivity. The ability to control loading of RNA by tuning the charge at the inner surface of a protein capsid could illuminate aspects of genome recognition by viruses and pave the way for the development of improved RNA delivery systems