Description of column headings for Tables a1 to a10

Spot ID

A prefix "M" is from E. coli cells harvested during growth phase in glucose-minimal media and "R" is from cells harvested at early stationary phase in rich media.

N-terminal Sequence Tag

The N-terminal amino acid sequence tag. A single upper case letter indicates an unambiguous PTHaa signal in the cycle. A lower case letter indicates that the PTHaa signal is close to the level of background noise or lag. Parentheses indicate that a cycle had two or more PTHaa signals. The order of amino acids in parentheses is from strongest to weakest PTHaa signals. An upper case "X" indicates no PTHaa signal could be detected above the background lag. A lower case "x" indicates instrument failure in

the cycle and no amino acid call. The symbol "XXXXXXXXXXXX" indicates that no PTHaa sequence signal was detected above the background lag during the entire sequencing run.

Sequence Tag Match to Genomic ORF

The observed protein sequence compared to the amino terminal sequence of the matching conceptual protein in the E. coli genome. The predicted sequence is shown and the observed sequence is in bold. An "*" in the protein sequence shows the observed start site based on the N-terminal sequence tag. An underlined amino acid indicates a discrepancy between the predicted sequence and the observed sequence tag. The predicted amino acid is shown. For query-sequence matching the internal region of an E. coli gene, the numbers of amino acids between the predicted N- and C- termini of the conceptual protein that match the start and stop sites of the sequence tag are shown in parentheses.

Locus - The E. coli gene symbol assigned to the ORF identified by the protein sequence. The symbol "NM" indicates that the query string was used to search the database, but no significant match was found.

cpI - The predicted isoelectric point calculated from the conceptual sequence of the protein.

opI - The observed isoelectric point of the protein calculated from the 2-DE gel (x) coordinate of the spot.

MW - The predicted mass calculated from the conceptual sequence of the protein. The units are kDa.

Mr - The observed mass of the protein calculated from the 2-DE gel (y) coordinate of the spot. The units are kDa.

O-abd - The observed abundance on the master 2-DE gel.

N-abd - The estimated cellular abundance of the protein species. The units are molecules/cell.