▁( S fb I ) ▁facil itate ▁attachment ▁to ▁various ▁host ▁cells . ▁ ▁M ▁protein ▁also ▁in hib its ▁o pson ization ▁by ▁the ▁alternative ▁complement ▁path way ▁by ▁binding ▁to ▁host ▁complement ▁regul ators . ▁ ▁The ▁M ▁protein ▁found ▁on ▁some ▁ser ot ypes ▁is ▁also ▁able ▁to ▁prevent ▁o pson ization ▁by ▁binding ▁to ▁f ibr in ogen . ▁ ▁However , ▁the ▁M ▁protein ▁is ▁also ▁the ▁weak est ▁point ▁in ▁this ▁path ogen ' s ▁defense , ▁as ▁ant ib od ies ▁produced ▁by ▁the ▁imm une ▁system ▁against ▁M ▁protein ▁target ▁the ▁b acter ia ▁for ▁eng ulf ment ▁by ▁ph ag ocy tes . ▁ ▁M ▁prote ins ▁are ▁unique ▁to ▁each ▁stra in , ▁and ▁identification ▁can ▁be ▁used ▁clin ically ▁to ▁confirm ▁the ▁stra in ▁causing ▁an ▁in fection . ▁ ▁Gen ome ▁ ▁The ▁genom es ▁of ▁different ▁stra ins ▁were ▁sequ enced ▁( gen ome ▁size ▁is ▁ 1 . 8 – 1 . 9 ▁M bp ) ▁encoding ▁about ▁ 1 7 0 0 - 1 9 0 0 ▁prote ins ▁( 1 7 0 0 ▁in ▁stra in ▁N Z 1 3 1 , ▁ 1 8 6 5 ▁in ▁stra in ▁M G AS 5 0 0 5 ). ▁Complete ▁gen ome ▁sequences ▁of ▁the ▁type ▁stra in ▁of ▁S . ▁py ogen es ▁( N CT C ▁ 8 1 9 8 T ▁= ▁CC UG ▁ 4 2 0 7 T ) ▁are ▁available ▁in ▁DNA