Zinc finger: a type of DNA-binding domain, binded by transcription factors
Characteristics: zinc ion coordinated by two histidine and two cysteine residues
DNA binding: Several zinc finger domains are often connected as a chain and bind to an α-helix in the major groove of DNA.
Aids in maintenance and stability of the nuclear membrane
Essential part of many enzymes (> 100), including DNA polymerase, carbonic anhydrase, ACE, alkaline phosphatase, metallothionein, superoxide dismutase, and collagenases
Zinc deficiency
Causes
Inadequate dietary intake
Acrodermatitis enteropathica: congenital deficiency of the zinc/iron-regulated transporter-like protein (ZIP)
Malabsorption (e.g., due to Crohn disease), liver, and renal disease
Total parenteral nutrition (TPN)
Chronic liver disease (esp. liver cirrhosis)
Bowel resection
Clinical features
Impaired wound healing
Inability to replace type III collagen with type I collagen
Dysgeusia
On the upper surface of the tongue, there are taste receptor cells known as “taste buds”. These cells regenerate frequently but the activity reduces when zinc is deficient, which causes dysgeusia.
Anosmia
Immune dysfunction
Male hypogonadism
Dermatitis
Perioral (a) and perianal (b) erythema and pustules can be seen.
