code: public ProteinSequence getProteinSequence(TranscriptionEngine engine) {
  		DNASequence dnaCodingSequence = getDNACodingSequence();
  		RNASequence rnaCodingSequence = dnaCodingSequence.getRNASequence(engine);
  		ProteinSequence proteinSequence = rnaCodingSequence.getProteinSequence(engine);
  		proteinSequence.setAccession(new AccessionID(this.getAccession().getID()));
  
  		return proteinSequence;
  	}
docs: Get the protein sequence with user defined TranscriptEngine
  @param engine
  @return