Surfactant protein B

Surfactant protein B
Identifiers
Symbol	SFTPB
Alt. symbols	SFTP3
Entrez	6439
HUGO	10801
OMIM	178640
RefSeq	NM_000542
UniProt	P07988
Other data
Locus	Chr. 2 p12-p11.2

Surfactant protein B is an essential lipid-associated protein found in pulmonary surfactant. Without it, the lung would not be able to inflate after a deep breath out. It rearranges lipid molecules in the fluid lining the lung so that tiny air sacs in the lung, called alveoli, can more easily inflate.

SP-B is encoded by SFTPB, a single, 11425 nucleotide long gene on chromosome 2.Mutations in this gene are the basis for several of the lung conditions mentioned above. Both frameshift mutations and several single nucleotide polymorphisms (SNPs) have been found correlated to a variety of lung conditions. A frame shift mutation responsible for congenital alveolar proteinosis (CAP) was identified by Kattan et al. Many SNP's have been identified in relation to lung conditions. They have been correlated to severe influenza, neonatal respiratory distress syndrome, mechanical ventilation necessity, and more.

Surfactant protein B (SP-B) is a small protein, weighing about 8 kDa.Proteins are composed of building blocks called amino acids, and SP-B is composed of 79 of them (Valine, alanine, phenylalanine, leucine, isoleucine, and tryptophan being found in the highest levels). Nine of these carry with them a positive charge, and two carry a negative charge, leaving a protein with a net (total) charge of +7. In the body, two molecules of SP-B stick together and form what is called a homodimer. These are found embedded into membranes and other lipid structures, SP-B is a highly hydrophobic, avoiding contact with water.

...
Wikipedia