WEB VERSION OF BLASTP
When you run a blastp query using a fasta file with multiple chains you can choose which chain's results to examine using a drop-down box that appears after the search has run.
The results for each chain will be listed separately.
For ease of searching you can specify the output to be a csv of your desired format (See blastp -help and look up the -outfmt option for more information).
Note that for some proteins, such as the 1EMS you chose for an example, the multiple chains are identical. When you get the fasta file for that specific protein it will only have one entry. However if you really need a fasta file formated so each chain has its own sequence you can get the fasta file for all PDB entries and extract the specific protein_chain you want.