The shelf life is related to many factors, storage state, buffer ingredients, storage temperature and the stability of the protein itself. Generally, the shelf life of liquid form is 6 months at -20℃/-80℃. The shelf life of lyophilized form is 12 months at -20℃/-80℃.
One of two assembly initiator proteins for the 30S subunit, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit. Ref.10 Ref.15 Ref.16
With S5 and S12 plays an important role in translational accuracy; many suppressors of streptomycin-dependent mutants of protein S12 are found in this protein, some but not all of which decrease translational accuracy (ram, ribosomal ambiguity mutations). Ref.10 Ref.15 Ref.16
Plays a role in mRNA unwinding by the ribosome, possibly by forming part of a processivity clamp. Ref.10 Ref.15 Ref.16
Protein S4 is also a translational repressor protein, it controls the translation of the alpha-operon (which codes for S13, S11, S4, RNA polymerase alpha subunit, and L17) by binding to its mRNA. Ref.10 Ref.15 Ref.16
Also functions as a rho-dependent antiterminator of rRNA transcription, increasing the synthesis of rRNA under conditions of excess protein, allowing a more rapid return to homeostasis. Binds directly to RNA polymerase. Ref.10 Ref.15 Ref.16