diff --git a/src/servers/model/query/atoms.ts b/src/servers/model/query/atoms.ts
index 0901023f9e11afe766c3688759b570b2a1b86e6a..4f38ba3d28da5aa2d2530ece44dd0d8484bcd60c 100644
--- a/src/servers/model/query/atoms.ts
+++ b/src/servers/model/query/atoms.ts
@@ -6,7 +6,7 @@
 
 import { QueryPredicate, StructureElement, StructureProperties as Props } from 'mol-model/structure';
 import { AtomsQueryParams } from 'mol-model/structure/query/queries/generators';
-import { AtomSiteSchema } from '../server/api';
+import { AtomSiteSchema, AtomSiteSchemaElement } from '../server/api';
 
 export function getAtomsTests(params: AtomSiteSchema): Partial<AtomsQueryParams>[] {
     if (!params) return [{ }];
@@ -17,7 +17,7 @@ export function getAtomsTests(params: AtomSiteSchema): Partial<AtomsQueryParams>
     }
 }
 
-function atomsTest(params: AtomSiteSchema): Partial<AtomsQueryParams> {
+function atomsTest(params: AtomSiteSchemaElement): Partial<AtomsQueryParams> {
     return {
         entityTest: entityTest(params),
         chainTest: chainTest(params),
@@ -26,13 +26,13 @@ function atomsTest(params: AtomSiteSchema): Partial<AtomsQueryParams> {
     };
 }
 
-function entityTest(params: AtomSiteSchema): QueryPredicate | undefined {
+function entityTest(params: AtomSiteSchemaElement): QueryPredicate | undefined {
     if (!params || typeof params.label_entity_id === 'undefined') return void 0;
     const p = Props.entity.id, id = '' + params.label_entity_id;
     return ctx => p(ctx.element) === id;
 }
 
-function chainTest(params: AtomSiteSchema): QueryPredicate | undefined {
+function chainTest(params: AtomSiteSchemaElement): QueryPredicate | undefined {
     if (!params) return void 0;
 
     if (typeof params.label_asym_id !== 'undefined') {
@@ -46,7 +46,7 @@ function chainTest(params: AtomSiteSchema): QueryPredicate | undefined {
     return void 0;
 }
 
-function residueTest(params: AtomSiteSchema): QueryPredicate | undefined {
+function residueTest(params: AtomSiteSchemaElement): QueryPredicate | undefined {
     if (!params) return void 0;
 
     const props: StructureElement.Property<any>[] = [], values: any[] = [];
@@ -79,7 +79,7 @@ function residueTest(params: AtomSiteSchema): QueryPredicate | undefined {
     return andEqual(props, values);
 }
 
-function atomTest(params: AtomSiteSchema): QueryPredicate | undefined {
+function atomTest(params: AtomSiteSchemaElement): QueryPredicate | undefined {
     if (!params) return void 0;
 
     const props: StructureElement.Property<any>[] = [], values: any[] = [];
diff --git a/src/servers/model/server/api.ts b/src/servers/model/server/api.ts
index 7744f348924647f67cbc6f84c062d4395de9f8cb..ced5f70163b88405cd57d6bcb47cdf4781a671fc 100644
--- a/src/servers/model/server/api.ts
+++ b/src/servers/model/server/api.ts
@@ -35,7 +35,7 @@ export interface QueryDefinition<Params = any> {
     '@params': Params
 }
 
-export interface AtomSiteSchema {
+export interface AtomSiteSchemaElement {
     label_entity_id?: string,
 
     label_asym_id?: string,
@@ -52,6 +52,8 @@ export interface AtomSiteSchema {
     type_symbol?: string
 }
 
+export type AtomSiteSchema = AtomSiteSchemaElement | AtomSiteSchemaElement[]
+
 const AtomSiteTestParams: QueryParamInfo = {
     name: 'atom_site',
     type: QueryParamType.JSON,