From Proteopediaproteopedia link
CRYSTAL STRUCTURE OF HUMAN ANGIOGENIN REVEALS THE STRUCTURAL BASIS FOR ITS FUNCTIONAL DIVERGENCE FROM RIBONUCLEASE
[ANGI_HUMAN] Defects in ANG are the cause of susceptibility to amyotrophic lateral sclerosis type 9 (ALS9) [MIM:611895]. ALS is a degenerative disorder of motor neurons in the cortex, brain stem and spinal cord. ALS is characterized by muscular weakness and atrophy.     
[ANGI_HUMAN] May function as a tRNA-specific ribonuclease that abolishes protein synthesis by specifically hydrolyzing cellular tRNAs. Binds to actin on the surface of endothelial cells; once bound, angiogenin is endocytosed and translocated to the nucleus. Angiogenin induces vascularization of normal and malignant tissues. Angiogenic activity is regulated by interaction with RNH1 in vivo. 
Publication Abstract from PubMed
Angiogenin, a potent inducer of neovascularization, is the only angiogenic molecule known to exhibit ribonucleolytic activity. Its overall structure, as determined at 2.4 A, is similar to that of pancreatic ribonuclease A, but it differs markedly in several distinct areas, particularly the ribonucleolytic active center and the putative receptor binding site, both of which are critically involved in biological function. Most strikingly, the site that is spatially analogous to that for pyrimidine binding in ribonuclease A differs significantly in conformation and is "obstructed" by glutamine-117. Movement of this and adjacent residues may be required for substrate binding to angiogenin and, hence, constitute a key part of its mechanism of action.
Crystal structure of human angiogenin reveals the structural basis for its functional divergence from ribonuclease.,Acharya KR, Shapiro R, Allen SC, Riordan JF, Vallee BL Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):2915-9. PMID:8159679
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.