Probably part of a periplasmic ABC transporter complex futA1A2BC (TC 3.A.1.10.2) involved in Fe(3+) ion import (ferric iron). This protein and futA1 (slr1295) are subunit proteins that have redundant or overlapping substrate-binding functions (Probable). The differing subcellular locations of futA1 (predominantly thylakoid lumen) and futA2 (predominantly periplasmic) suggest they may fulfill different roles. Plays an important role in protecting the acceptor side of photosystem II (PSII) against oxidative damage, especially under iron-limiting growth conditions. Plays an undefined role in copper supply to thylakoid proteins. Binds Fe(3+) in the periplasm. Transcript levels increase when cells are grown in the absence of iron. Periplasmic levels increase when cells are grown in high NaCl or in the absence of iron. Predicted to be exported by the Tat system. The position of the signal peptide cleavage has not been experimentally proven. Cells grow normally in the absence of iron; double knockouts of this gene and futA1 (slr1295) grow very poorly in the absence of iron and have a marked reduction in their ability to take up Fe(3+). Belongs to the bacterial solute-binding protein 1 family. There is some controversy as to whether this protein preferentially binds Fe(2+) or Fe(3+).