<i>RIO1</i>, an extraordinary novel protein kinase

Abstract

RIO1 and Rio‐related proteins display little similarity of primary sequence with conventional protein kinases. Based on secondary structure alignments, we show that it contains the domain structure (subdomains I–XI) and conserved secondary structure elements found in conventional protein kinases. We show that recombinant wild‐type Rio1p isolated from Escherichia coli displays kinase activity which depends on autophosphorylation and magnesium or manganese as ATP‐activating ions. An initial biochemical characterization of Rio1p is presented.