London, Feb 12 Scientists have discovered how a promising malaria vaccine target – the protein RH5 – helps parasites to invade human red blood cells, an advance that could lead to a more effective vaccine for the deadly disease. The study by researchers at the Wellcome Trust Sanger Institute in the UK reveals that a previously mysterious protein on the surface of the parasite called P113 anchors the RH5 protein, and provides a molecular bridge between the parasite and a red blood cell.