Sandbox Reserved 196: Difference between revisions

Ribonuclease B (RNase B) is a form of the enzyme RNase A that has an added glycoprotein with N-linked carbohydrates at <scene name='Sandbox_Reserved_196/Rbb_basic/16'>Asn-34</scene>, which means that the carbohydrate is attached at the <scene name='Sandbox_Reserved_196/Rbb_basic/17'>nitrogen</scene> of the Aspargine-34 side chain. This added sugar chain aids in the folding of the protein as well as cell to cell signaling<ref name="first">Varki A, Cummings RD, Esko JD, Freeze HH, Stanley P, Bertozzi CR, Hart GW, Etzler ME. ''Essentials of Glycobiology''. PMID:20301239</ref>. Glycoproteins play an important role in tumor formation because it has been found that N-linked glycans recognized by the CD337 receptor on "natural killer cells" are mutated in tumor cells, stopping their death<ref name="second">http://en.wikipedia.org/wiki/Glycan</ref>. Other than the attachment of the polysaccharide, RNase B is structurally the same as RNase A, but the attachment allows for additional catalytic activity. This small change allows RNase B to hydrolyze double-stranded RNA at ionic strengths where RNase A has no activity, showing that small changes in the active sites of very similar molecules can lead to new roles and activities <ref name="third">PMID:3680242</ref>. <scene name='Sandbox_Reserved_196/Rbb_basic/1'>(Return to original scene)</scene>