UK's PRS REIT gains on selling operating unit

** PRS REIT PRSR jumps 9% to 114p; top gainer on FTSE midcaps index MCX

** British real estate investment trust to sell operating unit to Waypoint Asset Management for 646.2 mln pounds ($881 mln)

** In addition to proposed deal price, shareholder's will get dividend of up to 1.1p/share payable in November

** As of last close, PRSR down ~3% this year