You may run SDS-PAGE of your samples and a blank control. Then compare the density of the target band.

Or, detect the target protein by westernblot to see the abundance,

Thank you very much for the response. But I need a confirmation through its NT sequence or proteomics or through some other means of theoritical mode. Because, we do not have the molecular facilities at our lab. so, we have to procure the strain from ATCC. Prior to procuring, we want confirm the strain details for the designated protien.

If you are looking to confirm overexpresion of a particular protein, you pretty much have to be able to detect and measure that particular protein.

It doesn't take much. If you have a specific mono/polyclonal Ab, alk.phos. labeled secondary Ab, nitrocellulose and alk.phos substrate you can do a quick dot blot to confirm overexpression.

I am sorry you are talking about over expression of heterologous protein (coded in plasmid) in Bacteria or in a cell line?

You want to induce the expression of the particular protein (coded in plasmid) right? please make it clear.

If I correctly understood your question, there is not a "a priori" or

in silico method to predict the yield of protein expression of a particular E. coli strain.

As a matter of fact, we routinely check few different strains with each new reconbinat protein in our lab. Consider that most of protein expression is done in BL21 strains that differs only in few specific features (pLys, Star, ai).

The only consideration that you could think of regards the codon usage of your protein. Dependin on its codon usage (i.e. presence of rare codons) you could decide to use BL21(DE3)RIL, RP, or Rosaetta strains.

What do you mean by strain? Is it a plant or prokaryote organism or a transgenic animal? would you use target protein antibody? Or biochemistry chromatography for protein analysis?

Generally qPCR used for gene expression in transcription level and Western blotting applied in protein synthesis. You can use same protein expression analysis in your favorite as well as control organism then compare the results

I assume that you are looking for expression of a native gene under the endogenous promoter sans epitope tags. S. Steffansson suggestion is a good provided the antibody for your particular protein of interest is commercially available or that you have an antibody that you generated that can recognize this protein.

You need to describe your question clearly. You will get proper answer. I felt Some point is missing from your question

To prove that your gene of interest is indeed overexpressed you will not come around wet lab techniques. This is not a big deal. If you can't do it yourself, get a coorperation partner who can do it. On the other hand: How do you want to work with a cell line without proper lab facilities?

If you want to limit the number of strains you obtain from ATCC, you may want to consider the following points.

Origin of the protein of interest: bacterial, yeast, mammalian etc.

Is it a synthetic construct, or are you obtaining the plasmid from another research group? Can you subclone it into different expression vectors?

Does the protein have any post translational modifications?

Are you trying to express full length protein or a domain?

Is your initial goal to express the protein in E. coli?

If the protein has PTM are you interested in refolding as in the case of disulfide linked proteins from inclusion bodies?

What is the ultimate goal of your project?

Bioinformatics tools can give you an idea if your construct design is correct in the case of secreted proteins (signal peptides etc.) but ultimately you will need to do the experiment.

Your question is not clear. First you asked about strain (modified) capacity to over produce specific protein. Secondly you asked about strain details.

If you want organism details go for biochemical characterization or 16srRNA sequence and DNA hybridization for specific strain .

If you want know protein expression go for SDS-PAGE with control.

If you want to know whether that strain producing that protein or not go for (molecular screening) construction of conserved primers against that specific protein and amplify the gene. Otherwise if possible use phenotypic screening.