Spermine synthase.
Spermine is present in many organisms including animals, plants, some fungi, some archaea, and some bacteria. It is synthesized by spermine synthase, a highly specific aminopropyltransferase. This review describes spermine synthase structure, genetics, and function. Structural and biochemical studies reveal that human spermine synthase is an obligate dimer. Each monomer contains a C-terminal domain where the active site is located, a central linking domain that also forms the lid of the catalytic domain, and an N-terminal domain that is structurally very similar to S-adenosylmethionine decarboxylase. Gyro mice, which have an X-chromosomal deletion including the spermine synthase (SMS) gene, lack all spermine and have a greatly reduced size, sterility, deafness, neurological abnormalities, and a tendency to sudden death. Mutations in the human SMS lead to a rise in spermidine and reduction of spermine causing Snyder-Robinson syndrome, an X-linked recessive condition characterized by mental retardation, skeletal defects, hypotonia, and movement disorders.
Pegg
Anthony E
AE
Department of Cellular and Molecular Physiology, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA. aep1@psu.edu
Michael
Anthony J
AJ
D000818:Animals; D041321:Chromosomes, Human, X; D006801:Humans; D051379:Mice; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013097:Spermine Synthase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D013096:Spermine; D013097:Spermine Synthase; D013095:Spermidine