PDBsum entry 4ynp

Transferase

PDB id: 4ynp

Contents

Protein chains

213 a.a.

193 a.a.

Ligands

SAM ×2

Metals

_ZN ×6

PDB id:

4ynp

Name:

Transferase

Title:

Ash1l set domain s2259m mutant in complex with s-adenosyl methionine (sam)

Structure:

Histone-lysine n-methyltransferase ash1l. Chain: a, b. Fragment: set domain (unp residues 2074-2293). Synonym: ash1-like protein,huash1,absent small and homeotic disks protein 1 homolog,lysine n-methyltransferase 2h. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: ash1l, kiaa1420, kmt2h. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.90Å R-factor: 0.265 R-free: 0.319

Authors:

D.S.Rogawski,J.Ndoj,H.-J.Cho,I.Maillard,J.Grembecka,T.Cierpicki

Key ref:

D.S.Rogawski et al. (2015). Two Loops Undergoing Concerted Dynamics Regulate the Activity of the ASH1L Histone Methyltransferase. Biochemistry, 54, 5401-5413. PubMed id: 26292256 DOI: 10.1021/acs.biochem.5b00697

Date:

10-Mar-15 Release date: 02-Sep-15

Protein chain

Q9NR48  (ASH1L_HUMAN) -  Histone-lysine N-methyltransferase ASH1L from Homo sapiens

Seq: 2969 a.a.

Struc: 213 a.a.*

Protein chain

Q9NR48  (ASH1L_HUMAN) -  Histone-lysine N-methyltransferase ASH1L from Homo sapiens

Seq: 2969 a.a.

Struc: 193 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: Chains A, B: E.C.2.1.1.359 - [histone H3]-lysine(36) N-trimethyltransferase.
• Reaction: L-lysyl₃₆-[histone H3] + 3 S-adenosyl-L-methionine = N₆,N₆,N₆- trimethyl-L-lysyl₃₆-[histone H3] + 3 S-adenosyl-L-homocysteine + 3 H⁺

L-lysyl(36)-[histone H3] + 3 × S-adenosyl-L-methionine (Bound ligand (Het Group name = SAM) corresponds exactly) = N(6),N(6),N(6)- trimethyl-L-lysyl(36)-[histone H3] + 3 × S-adenosyl-L-homocysteine + 3 × H(+)

• Enzyme class 2: Chains A, B: E.C.2.1.1.367 - [histone H3]-lysine(9) N-methyltransferase.
• Reaction: L-lysyl₉-[histone H3] + S-adenosyl-L-methionine = N₆-methyl-L- lysyl₉-[histone H3] + S-adenosyl-L-homocysteine + H⁺

L-lysyl(9)-[histone H3] + 3 × S-adenosyl-L-methionine (Bound ligand (Het Group name = SAM) corresponds exactly) = N(6)-methyl-L- lysyl(9)-[histone H3] + 3 × S-adenosyl-L-homocysteine + 3 × H(+)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1021/acs.biochem.5b00697

Biochemistry 54:5401-5413 (2015)

PubMed id: 26292256

Two Loops Undergoing Concerted Dynamics Regulate the Activity of the ASH1L Histone Methyltransferase.

D.S.Rogawski, J.Ndoj, H.J.Cho, I.Maillard, J.Grembecka, T.Cierpicki.

ABSTRACT

ASH1L (absent, small, or homeotic-like 1) is a histone methyltransferase (HMTase) involved in gene activation that is overexpressed in multiple forms of cancer. Previous studies of ASH1L's catalytic SET domain identified an autoinhibitory loop that blocks access of histone substrate to the enzyme active site. Here, we used both nuclear magnetic resonance and X-ray crystallography to identify conformational dynamics in the ASH1L autoinhibitory loop. Using site-directed mutagenesis, we found that point mutations in the autoinhibitory loop that perturb the structure of the SET domain result in decreased enzyme activity, indicating that the autoinhibitory loop is not a simple gate to the active site but is rather a key feature critical to ASH1L function. We also identified a second loop in the SET-I subdomain of ASH1L that experiences conformational dynamics, and we trapped two different conformations of this loop using crystallographic studies. Mutation of the SET-I loop led to a large decrease in ASH1L enzymatic activity in addition to a significant conformational change in the SET-I loop, demonstrating the importance of the structure and dynamics of the SET-I loop to ASH1L function. Furthermore, we found that three C-terminal chromatin-interacting domains greatly enhance ASH1L enzymatic activity and that ASH1L requires native nucleosome substrate for robust activity. Our study illuminates the role of concerted conformational dynamics in ASH1L function and identifies structural features important for ASH1L enzymatic activity.