Structure and Function Laura Martin HIV Integrase (IN) Structure and Function Laura Martin

Structure Three domains- the catalytic core, the C- terminal and N-terminal domains Catalytic core – contains active site responsible for catalysis of integration rxn C- terminal- binds both viral and host DNA N- terminal- unknown, but has zinc binding motif suggesting nucleic acid interaction3

HIV Integrase N CORE C (1-49) (50-212) (213-288) D-X(39-58)-D-X35-E H12 H16 C40 C43 D64 D116 E152 N CORE C (1-49) (50-212) (213-288)

HIV Integrase N-terminus Core C-terminus

Structure of HIV Integrase Full length enzyme (1-288 a.a) Catalytic core (52-210 a.a) C-terminal domain (220-288 a.a) N-terminal domain (1-51 a.a)

Structure of Catalytic Core Domain Central 5 stranded Beta- sheet with six surrounding helices -3 highly conserved residues (D64,D116, E152)

Why HIV Integrase is important! Total: 34 – 46 million Western Europe 520 000 – 680 000 North Africa & Middle East 470 000 – 730 000 Sub-Saharan Africa 25.0 – 28.2 million Eastern Europe & Central Asia 1.2 – 1.8 million South & South-East Asia 4.6 – 8.2 million Australia & New Zealand 12 000 – 18 000 North America 790 000 – 1.2 million Caribbean 350 000 – 590 000 Latin America 1.3 – 1.9 million East Asia & Pacific 700 000 – 1.3 million

Primary Structure of the Catalytic Domain

The N-terminal Domain -Conserved HHCC motif that binds Zinc -Probably functions in Multimerization -DNA Binding

DNA Binding Domain -Dimer -Each monomer is constructed of 5 stranded beta-barrel -Hydrophobic interactions between two, 3 stranded beta sheets

Integrase has NLS Pre-Integration Complex Integration Reverse transcription Pre-Integration Complex Nuclear import Integration

Function Responsible for covalent recombination of retroviral DNA with host cell chromosomal DNA within nucleus Integration catalyzed by HIV integrase Integrase performs a series of DNA cutting and joining First removes two nucleotides from each 3’ end of viral DNA Second step- strand transfer- joins 3’ ends to 5’ ends of strands of target DNA at integration site

HIV Integration Target DNA Viral DNA Provirus (2) Strand Transfer 5’ AC CA (1) 3’-end processing (2) Strand Transfer HO- -OH Provirus (3) 5’-end joining

Sources King, Peter Powerpoint: HIV, AIDS, Integrase and You Pieribone, Ph.d, Vincent. "HIV Integrase: A New Therapeutic Target." Treatment Issues (1995). 8 Nov. 2005 <http://www.aegis.com>. Robert, Cragie. "HIV Integrase, a Brief Overview from Chemistry to Therapeutics." Journal of Biological Chemistry (2001). 8 Nov. 2005 <http://www.jbc.org>. Subhendu Chakraborti Power Point presentation: HIV Integrase Last but not least Walsh, Matthew B., and Marcey David. "HIV- 1 Integrase The Catalytic Core Domain and Minimal DNA Binding Domain." (2001). 8 Nov. 2005 <http://www.clunet.edu>.