TRNA synthetases play a key role in protein biosynthesis by catalyzing the specific aminoacylation of tRNA at their 3' ends, a two step reaction termed "charging" of tRNA. The tutorial depicts the binding of glutaminyl-tRNA synthetase and tRNAGln. A uracil (U35) provides a key element for the recognition of tRNAGln by the synthetase enzyme. U35 of the tRNA is anchored in place by specific amino acids in the synthetase protein interacting ionically with the nearby backbone phosphates. Given what you know about ionic bonds and the phosphate backbone of RNA, what type of amino acids are involved in this interaction