原核生物核糖体的组成 Ribosome Small subunit Large Subunit Sedimentation 70S 30S 50S coefficient Mass(kD) 2520 930 1590 Maior rnas 16S(1542 bases) 23S(2904 bases) Minor rnas 5S(120 bases) RNA mass(kD) 1664 560 1104 RNA 66% 60% 70% proportion Protein number 21 polypeptides 31 polypeptides Protein 857 370 487 mass(kD) Protein 349 40% 30% proportion原核生物核糖体的组成 Ribosome Small Subunit Large Subunit Sedimentation coefficient 70S 30S 50S Mass(kD) 2520 930 1590 Major RNAs 16S (1542 bases) 23S (2904 bases) Minor RNAs 5S (120 bases) RNA mass(kD) 1664 560 1104 RNA proportion 66% 60% 70% Protein number 21 polypeptides 31 polypeptides Protein mass(kD) 857 370 487 Protein proportion 34% 40% 30%