An anti-sigma-G factor, prevents premature activation of sigma-G factor in the forespore; overexpression leads to 1000-fold reduction in spore formation, spore formation stops after engulfment (PubMed:17921305, PubMed:19497328). Overexpression also inhibits sigma-G transcription activation activity (PubMed:18208527). When both Gin and sigma-G are expressed in E.coli Gin inhibits sigma-G, strongly suggesting Gin inhibits by direct physical interaction (PubMed:19497328). Binds 0.5 mol of zinc/mol protein, probably 1 zinc per dimer. Probably functions as a homodimer (PubMed:19497328). Interacts with sigma-G factor, recognition occurs via the first 71 residues of sigma-G (PubMed:18208527, PubMed:19497328). Expressed starting 2 hours after sporulation onset for at least 7 hours. During sporulation under control of sigma-F factor. Premature expression of sigma-G factor (sigG or spoIIIG) activity during the early stages of forespore development (PubMed:17921305, PubMed:18208527). Spore formation continues normally (PubMed:17921305, PubMed:8759874). However its absence has deleterious effects on strain robustness and is strongly selected against in competitions experiments (PubMed:18208527).