and subsequently purified (often using Ni Sepharose resin if His-tagged) to be used as a "piece" or immunogen in experiments. Contextual Alternatives

In molecular biology, "RBD-991" identifies a DNA sequence fragment starting at the of the SARS-CoV-2 S protein gene (GenBank: NC_045512.2).

Depending on the field, "preparing a piece" for a 991 might mean:

, is prepared by digestion with restriction enzymes like and HindIII .

To "prepare a piece" involving , the process typically refers to the laboratory synthesis and purification of a specific fragment of the SARS-CoV-2 Spike (S) protein for use in research or vaccine development. Preparation Protocol for RBD-991

: The protein is expressed in a culture medium at 37∘C37 raised to the composed with power C