Table 2.

Four genes that were selected to construct deletion mutants

Number	Gene/product name	Putative function	Relative referencea
1	ribA	3,4-Dihydroxy-2-butanone 4-phosphate synthase / GTP cyclohydrolase II	[48, 49]
2	prtA	C5a peptidase precursor	[23, 50]
3	zmpA	IgA-specific metalloendopeptidase	[51, 52]
4	Putative aminotransferase	PLP-dependent beta-cystathionase / Maltose regulon repressor

^aPreviously studies to be associated with the virulence of S. pneumoniae