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I found this statement in my study materials in the section of Staphylococcus

The AG structure:

  • protein AG (species specific);
  • polysaccharide AG (serotype specific).

I know what is Protein A/G, a recombinant fusion protein that combines IgG binding domains of both Protein A and Protein G.

What is the point of this AG structure thing in the contex of Staphylococcus? Can we say that staphylococcus have AG structure? I think it has properties related to protein A\G and also to polysaccharide A\G. I know very little about polysaccharide A\G and not sure how it is related to serotype specificity in the context of staphylococcus.

Extension to the question

Antigenic structure of Steptococcus pyogenes: 
the group AG is unique, placing streptococcus in group A.

What is the AG here?

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up vote 3 down vote accepted

After puzzling over this for a while I think I have the answer . It's nothing to do with protein A or protein G. I think that whoever wrote your study materials meant Ag which is a common abbreviation for 'antigen'. I guess this was in the context of immune responses, or strain typing.

Looking back over your last few questions, it seems that you are at the mercy of a teacher who specialises in ambiguity.

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I added one more confusing statement which I do not understand about S.pyogenes. Do you understand AG there? – Masi Feb 6 '14 at 18:49
2 "a method of grouping beta haemolytic bacteria based on the carbohydrate composition of bacterial antigens found on their cell walls." – Alan Boyd Feb 6 '14 at 20:11

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